Originally Posted by
Darth Lefty
[MENTION=131875]andy k[/MENTION] I don't think Claris has existed per se long enough for anyone to wear it out from use alone. I suppose some level of Exage parts might be analogous. But there are similar MTB parts like Acera you can compare. My own experience has been good. After 15 years and thousands of miles including MTB abuse, the RD is still functioning just great despite significant and obvious wear. There's enough play throughout to let the bottom pulley wiggle side to side maybe more than half an inch. But that doesn't matter, because all the slop that would matter to the indexing is taken up by the tension of the springs. The EZ-fire shifters got gummy but they still work after WD-40 blast-out, the brake levers on the same pods are not too sloppy. The decals came off the shifters when I sprayed them out. The cassette I changed for gearing, not due to problems. The rest of the drivetrain (FD, crankset, chain) were not Shimano parts. I've lived in dry climates and stored it indoors or at least in the shade. If it were left out in the sun and rain all the time, or maybe worse, snow and salt, I don't know but suspect it wouldn't be good.
I think we're pretty much in agreement here. My experience with waiting for components to wear out before I upgrade has been like the old commercial with the owl trying to find out how many licks it takes to get to the Tootsie Roll center of a Tootsie Pop.
I ride in rain a lot, and after 5000 miles the teeth on the lower pulley of my Tiagra rear derailleur were starting to get pointy. By 8000 miles I'd have probably needed to spend $20 to replace the pulleys, but I think it's reasonable to consider those pulleys as consumables.
I just built a bike with a Shimano Eagle rear derailleur from the early 70's. I'm pretty sure that derailleur will outlast me with even a little bit of maintenance. I don't think I could break it with a hammer.