Except that the W123 is apparently built in such a way that everything is readily removable and replaceable. Because of this, and because the car wasn't exactly rare, spares are easy to come by and relatively inexpensive, and once you've fixed the thing, you're good for lord knows how long because there are so few things to go wrong in an old car to begin with.

The words Mercedes and (relatively) inexpensive do not belong in the same sentence. At least not in Australia! In this country if you walk into a spare parts supplier and say the word Mercedes, you can her their pants zipper drop in anticipation of what is going to happen next.