Buying W124

There's been 2 facelift models, so this doesn't clearify things but I'm going to assume you mean one from the last series, which is the worst series. You rarely see those around anymore unless they've always been in a hot and dry climate.

I daily my W124 but I own 2 so if one has issues I can take another one. If I only had one I'd be without a car for 3 weeks per year at least. You need a specialist to work on these cars. Any garage will tell you they can work on it, but they're full of it. Just because they're easy to work on doesn't mean the problems are easy to diagnose as well.

Don't ever think you're done with these cars. They're 40 years old. Even one that's been meticously maintained will have issues that'll eventually leave you stranded one day. You'll constantly be facing new problems because every part has its own lifespan. Expect to shell out 1 to 2 k annually to keep it in great condition.