Wear tangent: Ditto what Jenn says. Remember, she and I wear our jeans HARD. The worst case was within a season -- pair of jeans from J. Crew. They wore out in inner thighs. They weren't even tight. I had purposely sized up. Who knows. Maybe that was the problem?
When my kid was a toddler, I always wore through the knees -- sometimes after only a few months! Especially one knee. Why? Because I was always getting down on the ground to be at eye level. Yes, I patched them. But patched jeans are not really consistent with my style. Luckily, that doesn't happen so often any more.
I've also worn through at belt loops (fixable, to a point) and sometimes it's the rear that starts looking thin. Once my cat got his claws in a pair and made a kind of run in them -- or at least a very obviously pulled thread, and this in turn weakened the fabric overall. And sometimes they just fade too much. I don't mind some fading -- that's fine. But I tend to like at least one dark rinse in rotation so if all of my jeans are on the light side I will be looking for a darker pair to add.
I have lots of jeans, too. It's not like I wear the same pair all the time. But I do favour certain ones. I'll easily wear my favourite 2 pair more than 150 times each per year.
Who knows, right? Some people are just harder on stuff, I guess. I have friends who go through tops a lot faster than I do-- they perspire more, I guess, or stain/ spill more. That is rarely my issue. For me, it's footwear and jeans all the way, with knits a close contender for wear -- in fact, I probably hang onto most of mine somewhat past the "best by" date just because it infuriates me that they tend to look tired so soon!