Anyone finish a long campaign and it ended happily with all players still there?

7 year campaign, 100 sessions. Lots of interruptions, a hiatus in there, but in the end we went from session 22 to 100 with the same roster. I was the DM. They slayed the big bad, returned victorious, we did a wrap up and epilogue bit. Then I just cried. I was so happy, relieved, fulfilled. Others cried too. It was amazing.

We have other campaigns with overlapping people, but something tells me nothing will come close to that one.

I think about 4/5 of games I’ve played or DMed fizzled out.

But that changed when I found a solid group! We are now one session away from ending our second campaign! The first campaign was 2 years and the second a year and a half. All original players still present and happy. I’m going to be real sad when it ends next week…

Edit: for your situation, why not ask the remaining players if they want to see it through or start something new with a few new people? I think you could totally finish your current campaign if the players are up for it! The story might shift or stray a little, but that’s how D&D goes anyway!

The majority of campaigns I've been in that had an actual Ending had good, if not happy, endings

One I ended one that way but mostly no some games fizzle out and sometimes I have had one or two people leave 

Yes. About a year and a half ago I had a 4-year campaign end happily and with all the original characters (and players) there. Before that, I had a similar length game that did the same thing (although, I'd say that one of the players was happy but the character was not - the player likes tragic characters).

Just my observation and thoughts (DM for over 10 years), and to preface, I'm mainly going to be talking about homebrew vs modules, because modules are harder to tweak since you're usually following a prewritten story:

If you don't want a campaign to fizzle out or lose steam, a common mistake is to have no clear direction/overall goal they're moving towards, the "get the ring to Mordor" type of thing. This doesn't mean there's no roleplaying, tangents, fun side quests, etc, but it's the thing that unifies the reason why they're a group in the first place and why they're "leveling up" or simply growing as characters.

This will inevitably force you to have the ending in mind already, and give you an idea of what you want the lead up to be to that. What this will do is give you flexibility and structure - if you notice your group is losing some interested on random things in between, you know how to get to the ending. If you notice that the group is loving the path to the end, you can prolong it.

In other words, DMs need to be okay with ending the story, and the more experienced a DM gets, they will know when that needs to happen based on their specific group. Having the ending up your sleeve (even if it's vague to begin) is very helpful to do this.

As a DM, you can make the ending the way you think your group would like. Some players may even want their characters to retire in death, or you can have all of them survive by giving them a doable combat scenario. Or they can all go out in a blaze of glory but complete their mission by doing so. You'll most likely know your group by this point and you can even ask them individually how they envision their character by the end of the story.

I've had campaigns that lasted several years, 1 year, 6 months, 5 sessions, one shot, etc. They've all ended differently and they all were really fun, because they were tailored to the group and how things in their personal life were playing out regarding scheduling. For example, one of the player's work schedules was about to conflict with our regular playing time, so I timed the ending of the campaign to be his last day playing the campaign. Putting the players and their characters in the center vs the plot will give a good indicator when things need to shift. TTRPG is a dynamic, changing, and flowing storytelling medium, which is the beauty and uniqueness of it.

To answer your question, if you're bringing in new players, ask your existing group if they'd like a new story/characters. If they want to continue with their existing characters, create a new arc for the new players to start fresh with. And have an ending in mind, and make it clear this is what the group is moving towards (this is what Session 0 is for, to get everyone together to discuss what type of party they want to be and what they want to accomplish as a party).

The way they roleplay through the various sessions will give you an indicator of what kind of ending it will be, but be sure to keep them moving toward that ending, and do end it eventually.

When I started my Table, I had a pretty simple rule for myself.

Its like a Chess Club. It happens every week. Whoever is here, we play with. Anyone who can't make it (almost) every week, can't be part of the team. I have no interest in having a session every quarter of the year.

I alternate between short campaigns (running about 6 Months ~ 25 Sessions) and long campaigns (1,5 - 2 years ~80 Sessions). So far we have completed 2 long and 2 Short Campaigns and are in the middle of our third long campaign.

Oldest player joined 7 years ago. Nobody from the first Session is still there, but I went through a lot of players in the very beginning before I had a stable table. 3 of the 5 players who finished the first Adventure with me still play on my table. (Though the third just had to leave a week ago.)

It can be done. Easily. But not with everyone. There are just many people who you will never get onto a weekly table and thus, have only a theoretical campaign that fizzled out somewhere in the middle over the years.

Its a question of: Do you want to hang out with these people specifically, or do you want to play?

Because that is simply often not compatible.

Just finished one a few months ago. 3 years, about 70 sessions with various breaks and hiatuses. We lost a player at session 6 but from there we kept going strong.

The best advice I can give for players and DMs is to just.keep.going. It seems like it’ll be difficult to manage with players entering/leaving all the time, but it’s more than worthwhile to continue the narrative. It’s like finishing a long movie. Sure there are points you may not like and characters that leave along the way, but you still have to see how it ends!

twice in over 2 decades. One of them had a wonderful ending where the characters had a little epilogue where they were talking about all their old adventures over a game of cards with a couple of demi-gods. They were prisoners of one of those demi-gods who kept them in a museum of sorts where he stored all the magical items he'd collected... but they get a yearly card game to hang out and reminisce... so that's a good ending right?

Quite a few for me, though it's not the majority. Usually there's a "Hey I want to wrap up this campaign after <this or upcoming such and such> adventure conversation that takes place.

I think for most of us something comes up in real life so that we stop playing too long or the existing DM says, "How'd you guys like to play a Star Wars game? (or some other genre). It's hard for players to turn down lightsabers

Never played/ran a campaign where all the original players or characters saw it through :(

45 year campaign world (playing for 52 years).

Plenty of times.

Enjoy. Worth every minute of it.

If we don’t count the death more than one long game yes

Yep sure did. Most of them fizzle, I guess it’s 1/3.

Typically the games that end properly provide fodder for future games, NPCs that used to be PCs are the most likely, or visiting a place 100 years after the party changed something and seeing how it turned out. 

We played a game set in Saxon England that included a bit of time travel. The missing Ninth Legion of the Roman era hundreds of years before, was missing because it had been pulled out of time. In the process of dealing with all this, my Mastermind rogue figured out time travel and at the end of the game he slipped away from various consequences by jumping into the time rift and vanishing from all knowledge.

Now we’re playing a Bronze Age Collapse game, and due to some subtle hints by the DM I have realized that we did NOT in fact meet Theseus, we have met my old PC come back in time and masquerading as Theseus doing some kind of nefarious plot.

I'm currently in a campaign that's gone from 1-19. Out of 5 PCs, we still have three original PCs.

Edit: I think I missed part of what you were saying. All the players are the same. We just had a couple of characters die.

Finished Curse of Strahd after about 60+ sessions over 18 months with five players. Two of my younger brothers and three close friends which also includes a set of brothers who live in the same building as I do.

We just started a new campaign and doesn't look to be slowing down.

I've taken several games into the 'several years' range. Most started and finished with the same group, but I recognize that we've been lucky in that regard. And it takes not a small amount of effort on my part to make sure we keep at it (I'm usually the DM).

One of those campaigns went 1-18, switching editions partway through (players option 2e to 3.0 to 3.5-ish - I wouldn't do that again), and had the same core of 3 players with a few others rotating in and out.

I've had 2 campaigns, one was 7 sessions (it was just lmop) and 1 was 30, both had at least one player leaving during them for various reasons, but those who stayed to the end got to see the end happily and it was a very satisfying feeling, especially for the longer one.

Finished 2 fully another one I had to speed run thanks to players leaving so I don’t really count it. 3-4 I never finished or they just fizzled out. Usually because of players flaking out etc. it is what it is.

Yes it was awesome! 5 years of role playing the same character, a bard from Advanced Dungeon and dragons. It was a joy and I loved every minute of it! I still think about that game and how much fun I had!

My current group has successfully completed 2 campaigns. The first took 3 years. We ended up at level 17/18 from level 1. Kinda saved the world, but also found out the world we were saving was a self-created matrix.

Very glad to see so many people who've experienced good ends to the campaigns :)! Love hearing all these stories. With that in mind do you think I should try again then? Or keep going with what I have? We are still level 10 for context 🥹

I have one game that reached a fairly satisfying conclusion. Started at lvl 1, ended with the party ascending to Godhood. Those PCs now make up the pantheon of my homebrew setting.

I had 2 end well. The first one was the first campaign I ran, which was a curse in disguise I think. Because since then I’ve had to deal with players with problems keeping focus, people coming in and causing trouble, other players insisting on DMing despite the fact that we’re in the middle of a game, etc. this first one they made it all the way through the temple of the old god, battles wits and clashed swords with the thing, and one of the NPCs died sealing it away, the players were emotional, and the players from that game who I still talk to, still talk about it years later.

The other unfortunately, ended very early, and I had to wrap up a several year game in about 2 weeks. The outcome was actually really nice, they got to the country they were trying to get to, and saved/backed up by reinforcements. A very satisfying and hopeful outcome. Unfortunately the group its self was falling apart and they were actually supposed to have a hand in how the war of the game’s world went down, and that never happened.

I’ve run a total of 6 long term campaigns, and so far only two ended well. I’m in the middle of curse of Strahd now, and some of the players are starting to get excited and want to DM their own games again, and it’s honestly irritating the crap out of me.

Edit: description of first campaign.

If it were for the initial players, I'd only have one remaining lol

Thankfully I was able to find other people to replace the few I lost, and they are still persevering

I actually just finished my 6 year long campaign last weekend! https://www.reddit.com/r/rpg/comments/1cqkd1e/well_i_guess_its_time_for_one_of_these_posts_i/ 

I joined around level 17 and went to 20. Everyone was happy except the DM who began to feel there was no point since we would always have the power to find a way to solve or bypass every problem without breaking a sweat.

I think we started to suffer from what you might call the X-Men film issue or something... It's easy to care about saving a villager but hard to feel the same emotional connection when the entire world is being destroyed - on paper it's bigger, but in reality it sparks no emotional connection.

3-4 year campaign.

All original players finished except one. We played online (Roll20) began during COVID lockdown and after..

About a quarter or halfway through one of the players couldn't keep making it. Near the end of the campaign he showed up again but eventually ghosted, so he never got to finish.

Now we're hanging out for the next one but our DM is about to have a kid (plus study, plus life in general). So either myself or one of the other players is trying to figure out a campaign.

I finished a 2 year campaign with my group that started during COVID and we started a second campaign in the last 6 or so months. We’ve slowed down a bit because of life things but are still playing at least once per month.

Me and 2 others ran a 3.5e campaign from level 5 - 15.

We started as level 3 rogues that got adopted into a royal family. We trained into Duskblades (as this was our family's class specialization).

Our dad (the king) got kidnapped, and us 3 brothers were duty bound to rescue him.

Around level 12, we found our father and safely got him home. Sadly, 1 character died on the way home. Luckily, I had 1 boon to be granted by a dragon because I didn't let my brothers steal their eggs. ( Obviously, I wished for a homemade spell and an intelligent weapon!) LOL, No, I asked for brothers' life back. This ended the campaign.

6 months later, we decided to restart the campaign at level 16, and we ran it to level 22 before it ended. No one died!

1 month later( DM needed time to set up more storyline), we jumped back into the campaign! It started with a seige on our city, some investigating to discover a god had it out for us, then a journey to weaken said god till we felt confident enough that we could beat him.

Around level 25, 1 of us rolled 3, 20s in a row. My DM rewarded with an auto success but kept a record that it happened. Level 27, the other 2 characters rolled trip crits.!

We were rewarded at level 28 with a choice. 2 level ups or demigod status( access to god feats) we all took demigod status!

CHARACTERS:

1. PENNINAU: (3) Rogue/ (15) Shadow Sorcerer/ (9) Duskblade/ (1) god (Specialized in Shadow Magic, obviously)

2. ANDRIX: (3) Rogue/ (10) Beguiler/ (12) Duskblade/ (1) god (Specialized in Fire & Illusion Magic)

3. [Me]: (3) Rogue/ (4) Paladin/ (16) Duskblade/ (4) Vampire/ (1) god (Specialized in Ice & Blood Magic)

What made this campaign so great was the details that went into starting these characters.

At level 3, we rolled personalities, flaws, likes, dislikes, allergies, relationships, morals, etc.. Our DM even drew up some awesome art of our characters.

To this day, I'd like a chance to replay this character, even if I had to start over!

I've lucked out mostly, got a campaign that's coming up to it's 4th year and we're 130+ session in and everyone has been there since day 1

I also have another group where we've finished 6-7 campaigns and we're gearing up for our next one. We've had a few people drop and come in by never mid campaign, just the campaigns weren't to their tastes.

Yeah, I've had several campaigns last years with the same players and ended well. But I think that's rare.

These days I prefer shorter campaigns. More like single adventures with side quests really.

Also if you're going to mention critical role, campaign 1 actually didn't retain all the players till the end. They split ways with one of them at one point (for a few reasons).

I've had several year+ long campaigns with the same people from start to finish, and more where just one person left. I count myself lucky for that.

Finished a 2 year epic sci-fi space opera with happy endings all around. It was the best campaign I've ever run.

I had a 3.5 game go 6 years, had one very early player switch (around level 3), finished at level 17 by preventing the Cabal they had been opposing from summoning a Demon-God to the planet.

Was able to write an epilogue from the perspective of an NPC about the surviving party members, and the campaigns effect on the world.

My players are to experienced and dumb choice makers for all to survive. I have to over tune encounters in order to provide a challenge and when presented with a door to an orphanage in a deserted town, that has thumping sound comming from inside, they open it every single time.

We finished a campaign by accident.  My character accidentally broke the world.  We "won" defeated BBEG by proxy, and all retired.  

We play every two weeks.  My character accidentally breaking the world happened at end of session.

Next session, DM did a quick recap of the consequences of the ridiculous move I made and then said "OK.  Let's talk about the world for our next campaign and start rolling up those characters...."

So, effectively, a down session and then we started up our current campaign.

We were all surprised, but no one was all that upset - and we all embraced the opportunity to make new characters.

27 years, one world one story multiple group changes over the years. The last group of 7 after four years dropped down to 4 but the main story and all the sub plots came full circle and it was a grand ending that even the previous three came to the final game for.

Gave everyone who showed up a commemorative pen knife shaped like a feather (a theme in the game) with an engraving that read, “Hero of Paradigm” (the name of my campaign).

I run into players from that game who still talk about the game and have the knife. Very rewarding.

We had a game run through ice spire, to Frost maiden and Avernus, three years, 1-20. It was amazing. I've had smaller games finish as well. It's just getting lucky with a group and your schedules meshing well

4 year campaign, 106~ session. Started in highschool, now everyone got jobs or university and it's been hard. But i'm trying to keep it up! Tomorrow is the first session in 4 months

70 some odd sessions in about 2 years, happy ending! Sadly didn't get to continue for a campaign 2 but got another amazing group now!

Sure, played in two campaigns now which went to 20 with nobody leaving. DMd a 1-20 campaign for all the same people (although one person joined partway and then left again). Nobody has rage-quit. My 2nd campaign we had some attrition because of interpersonal relationships.

It helps that I DM adults. 3rd campaign is at Level 7; we'll see if we can do it again!

The first real campaign i dm'd got finished in about 6 months.

Same 3 players start to finish.

Small group + short campaign + weekly meets = good pacing.

In my experience,  theres nothing wro g with a short campaign. It ensures everyone stays together and doesnt lose interest. Longer campaigns are cool but i rarely see them finish.

3-ish months ago my group started campaign 2 after fully finishing campaign 1 with the OG players + 1 more that joined about halfway through

I'm fairly lucky to have had my first campaign I ran end with everyone at the table, even then because our Fighter player helped ensure the Ranger, and the two Barbarians could absolutely make it for the finale, as they had real life come up near the end but still got to experience the ending.

Just finished a 2 year campaign. Throughout, a player was asked to leave due to inconsistency in appearances, which affected the high RP aspect of the game. All players were asked their opinion on this and reached the general consensus of removing the offending player. Their character was narrated to join the legion of the BBEG, considering they were a warlock and their patron was an offspring of said BBEG.

Their position was soon filled.

Wizard had died number of times, once even by consensual, though non sexual, asphyxiation (long story). But was always revivified.

A few sessions from D-Day. We were halted by a road block. The DM had brought back the player, with a few of their imps to try and halt us in our path. Our party tried to convince the player to rejoin us. And with some stellar RP, we made a deal. She rejoined us.

A couple more sessions pass, RP heavy, discussing our best course of action defeating BBEG, now with the insider scoop from the returning player.

Finally, final session day arrives. Guess who doesn't show up? Yes!

Even though that player didn't show, the session proceeded and was very entertaining.

The wizard however, made the big sacrifice. And died saving the world.

Outro, DM beautifully narrates the state of the world after D-Day. He asked us, individually, what our characters would be doing, years later. We each had our moment.

Epilogue, BBEG second in command, has resurrected the wizard, keeping his "brilliant" mind as a pet.

Best campaign, best players and best DM I have ever had.

I'm not sure what qualifies as a 'long' campaign. I have to say Demon Lord cured me of running meandering open ended campaigns.

Weekly sessions for about 6 months levels 0-10 seem ideal to me now.

Seems to me that people who make a game (whatever that game is) their entire life, have a bunch of problems. This will lead to issues.

Of the campaigns I've ran, I've finished 1/4. One fizzled out, one ended just 3 sessions from the end (2 players moved away), one is ongoing (around 12-15 sessions). Of the 4 campaigns I've played in, only 1 finished with around 20 sessions. The others lasted less than 5 sessions each before the DM quit

In one campaign I played we started (I believe) with 5. One left, another joined, 2 left and we eventually ended with 1 DM and 3 players. That group stayed together for the entire campaign which ended last year (after over 5 years of play).

You can always add new players into an ongoing campaign. I think it would be unfair for the players that have stuck with you to just restart the campaign (at least make sure they have a meaningful conclusion).

I did. Just last year we finished a 3.5 year campaign with 6 players and .myself as the DM. We played nearly every week counting just shy of 150 sessions and it wrapped up wonderfully.

My group ran a heavily-modified Dragon Heist campaign where all four of the potential antagonists were in play, along with a few new ones. Our party was able to come out on top, and we decided to put our reward money together and open up a tavern together, then use what was left of it to purchase real estate on the city and let some of the poorer Waterdavians stay there for free. We ended up becoming beloved local heroes for how much we helped the less fortunate.

The whole campaign took about two years, we started at level 1, and we ended at level 10.

Now a few of us are playing in a sequel campaign as different characters, with our old party as background NPCs who are still doing their thing, but who aren't the heroes of this new story.

2 campaigns with the same 6 players, so be left for medical school - Over 700 hours of gaming. were playing a 3rd together now!

Almost.

4-year campaign I was running, and our druid player decided that during a 3 day period when he was about to move apartments that he was going to procrastinate everything until the day of our finale.

Our entire group was aware of the move and offered to both help move and help him schedule his packing, but he refused assistance and just up and chose to flake without telling us until 2-ish hours into the session.

Finale was absolutely banging and an incredible boss fight.

I DMed a Phandelver Campaign for 3 friends and my husband that did get completed with all still there and (I think) happy campers at the end. I also have been a part of a neighborhood campaign that has actually had one complete arc with characters that got retired at around level 11 and we have started another arc and our characters are level 5. No one has left for the entire thing. Pretty cool, our DM puts in a lot of effort so I guess it keeps us all around! Plus most of us are good friends so the dynamic is great.

I’ve been DMing a game for the span of 3.5 years, with a out 78 sessions. Lots of breaks and missed sessions. A year long hiatus at one point. Two players had a falling out and were replaced post-hiatus. Still going strong at one session every 3-4 weeks despite myself being on a 14 hour difference 😅

Normally, my campaigns are run in a set time, and they normally all survive (massive power scaling done by me) until the end where I release absolute hell and let then run wild.

I sure did!

Over 4 years I had two groups playing in the same world at the same "time" so what one group did effected the other.

Group 1 started and was weekly for 3-4 hours. That went on hiatus due to work and moving, but I started group 2 as a monthly (or sometimes twice) game playing about 5 hours a few months later.

After about a 6-7 months of only group 2 running, group 1 started again as an twice monthly game.

At that point they ran concurrently for 2 years until group 1 finished, then 3 months later group 2 finished.

Group 1 was about 100 sessions of 3-4 hours over 4 years. Group 2 was about 40 sessions of 5 hours over 3 years.

As to players, group 1 started with 5 regulars. One didn't come back after the hiatus, and had a few pop in here or there for some short stints, so 4/5

Group 2 started with 8. Lost 2 pretty early, then lost another after about a year and gained one about the same time who stayed for the last 2 years, so 5/8 plus one that was there for the last 2 years.

I can't say for sure if they were tears of joy it was finally over or if it was just a good ending to the story, but most of them still play in my new campaign, so I think it's safe to say it was more the later than the former.

Either way, I've been really lucky.

3.5/5 of the way thru a Descent into Avernus campaign (currently 8 months in,) we've added 3 people but lost one for a running total of 8 players excluding me (DM)

About 100 sessions over 3 years. No player deaths. Got very, very close repeatedly, but the party was Wizard, Warlock, Bard, Cleric, Paladin. Warlock and Wizard (me) managed to position pretty well in most combat scenarios to avoid too much stress after like level 9. Cleric had sone super clutch heals at mamy points. Paladin had the cloak of displacement (iirc) that gives disadvantage on all attacks unless they're hit, so they even had a 1v1 with their personal story bbeg and managed to avoid being hit the entire fight. There were lots of fun and epic moments like that. Aside from a few moments, the vast majority of the campaign everyone played really well, and the DM rolled like crap lol.

Levels 1 to 14, after defeating the BBEG and saving the world, the Paladin went back to his life on a farm, Cleric went back to her people, Warlock succesfully bargained to end their pact (and lost their memories) but also managed to return to her people, Bard and Wizard are set to do an epilogue set of sessions (with the other party members playing mercenaries) where they have some plane hopping shenanigans chasing a wizard and wrapping up their plot lines.

Should note that this group invited me for that campaign (and we are in another now) specifically because the same DM near-TPKd their last campaign 2 times before finally succeeding. I think we got incredibly lucky with his consistently unlucky rolls (he'd roll a 20 on the enemy's perception but then roll sub-10s regularly to hit), cause in our next campaign he nearly TPKd us in the first big combat.

6 month campaign that ended well and one of the players took over DMing!

One other 1+ year campaign that should’ve taken 6 months but is still going on due to delays and scheduling

Bit of a mixed bag but it is what it is

curse of stradh. it took about 8 months. some weeks we ran three 5hour sessions. we finished with only 1 death in the party and all got our happy ending! (and the entire party was the same party from day1)

247 sessions long, level 1-20, all of my players were offered to ascend to godhood but they all refused so very dramatic and wholesome ending (little advice: use Hollow Knight OST if you want background music, it is very fitting more often than not

I've run a couple of campaigns, one all the way to 20th level, with the "same" group. Only one player has been there for all of it, though a few have been there for a long time, and one recently came back.

When a player leaves, just fill their seat and move on. The ship of theseus is still a ship.

To your question, I would keep going, without stripping out any of the content your previous players added. Unless it's silly or whatever. Don't rip it out just because the player left. That player's character just becomes an NPC and leaves to focus on resolving their backstory, or pulls back into a support role. The new players will bring their own backstories and goals for you to weave into the campaign. This will make your game world richer and more involved. Definitely a good thing.

Anyone finish a campaign?

Mid campaign, current one going on 4 years of mostly weekly sessions (current started in 2020, so it was basically "the world's ending, should we get the band back together?"). It's possible, people just have to prioritize it a bit and frankly defend their nights against work interruptions when that's possible. Same group has been gaming for a long time, we'll go for a few years, take a year or two off from campaigns to play other stuff. We've had to work through the usual set of life events with marriages, kids, health, etc, and it's all online now since we're spread out. We've reached an end to at least a couple years long campaigns, and in a few other cases reached a point where we were done with a system or a plot and just called it.

So yes, can and does happen. Keep it going, get new blood in, use their lack of context to do some role playing; nothing wrong with a recurring villain stopping mid-speech to ask who the hell some new opponent is, or a new player getting to spy a bit because they're an unknown to the bad guys.

On hiatuses, the better the notes, the better you can pick back up. We keep a running word doc for the group to look back at the game so far.

Yep. 2 and a half years after I started running a campaign for my friends and it ended spectacularly with the players humiliating the big bad in the most satisfying way. We even came back to the game for a few sessions to have a post game adventure a year or so later.

If I don’t count the “that guy” player having 3 characters with one leaving, 1 betraying the party, and the final one actually being decent? Then yes, a 2 year long under dark campaign. If not, then yes a 1 year long water deep campaign

6 year campaign over 8 year span. First and only group I've DM'd to actually make it from lv1 to lv20, and I really made em earn it.

Absolute life milestone for all involved.

Did a 6 year campaign. Not everyone who started made it to the end but a good chunk did.  At the end the person with the shortest duration was like 4 years?.  The game as a whole saw 8 regular players

2 quit in the first 3-4 months 2 made it from session 0 to the epilogue

2 quit after about 4 years by moving across the Atlantic. 1 died. 2 folks got added and were my youngest's namesakes.

I just finished a 6 year, 1-20 campaign. We had some dropouts very early on, and a new addition later, but we did have the same crew probably from around level 4 or 5. They killed the BBEG and saved the world

My pals and I all started together and we’ve completed a campaign together. Me and two of the others rotate as DM’s and two of us are running a campaign side by side currently.

We’ve had one player drop (also a pal) due to work schedules but another stepped up immediately.

Never played with people outside of my pals so I can’t speak objectively but subjectively, great success.

i used to have a really bad track record when it comes to finishing campaigns. then i met my current group, we did 4,5 years of taldorei (level 1-20) and finished strahd and spelljammer. so really its all about having the right group.

I had a campaign that ran 5 years over 150 sessions. The ending was very satisfying though not necessarily "happy"; it was symbollic.

In my experience, the best thing to do is to over-recruit players and play every week no matter who can show up. Over time, you might go through many players, but you will actually get to play, which is so much better than the alternative. And you will be left with a table of people who actually want to play with you.

I just finished up a five year campaign (~175 sessions) this January, and we actually had two more players than we started with. I started running it in college and one player couldn't join for the first semester. 

The other was a guest player I brought back toward the end, who made the 'mistake' of using coming to ask if his character's character (a Paladin/Sorc multiclass) would be helpful in one of the final big boss fights (against Vecna). There was no world in which the answer wasn't no, so he ended up hanging around for ~50 sessions and both of the final major boss fights. He seemed to have a good time, and everyone else did to, so no harm no fowl but it had not been the original plan, lol.

I'm finishing up the other campaign I are started in college (6 1/2 years, ~225 sessions) next weekend. They had a little turnover the first ~12 seasons when one player dropped and a new player joined, but other than that everyone is still there.

That group has been through ~20 different characters over the course of the campaign, though. We did manage to mostly get the original batch of characters back together though. Mostly.

I'd say that ending a campaign is definitely worth it. The final sessions I ran in January were done of the most emotionally satisfying I've ever run, and finishing that story was a wonderful thing for everyone involved. That said, something that long will take way longer to wrap up than you expect, especially if the last year of sessions are at level 20.

I ran a campaign that spanned 2 years of weekly play with all of the players still there at its conclusions and after than another long campaign with a different group set up that was 1.5 years with everyone there at the end. I've not had as much luck since then, but we're all getting a bit older and busier so it makes sense

So we play Pathfinder and generally run adventure paths, Ive been playing with the same core group for 20 years but there's been kind of a revolving cast outside the core group, we have however finished 2 adventure paths with no change in roster, 1 with 2 players leaving at like level 5 and 1 of them got replaced at that point and 1 player left at like level 12 and didn't get replaced. We are about to finish another campaign with one player dropping out like halfway through but everyone else still there. We also have 2 campaigns that are on hold due to dm burnt out but which have not lost any players and a few on hold that have lost players... It's a mess outside of the core group basically lol but we've had some good luck in there