Originally Posted by
wphamilton
Is it even possible to need a whole new drive train all at once, if you've never replaced parts of it? Not even including the "end of life" shifters which I'd disregard on general principle, but I think wear the cassette, chain, and/or cables would make the bike unrideable before the chain rings get very worn. Unless you have some kind of ultra-light aluminum rings or something?
Perhaps the shop is making the might-as-well-do-all-at-the-same-time-to-save-on-labour argument. OP did mention that the shop measured the chain with some kind of tool, so I change that first. It's the lowest hanging fruit in this whole thing.