Which Levis do you buy? Do you buy the crappy stuff you find at Wal Mart, et al, or do you get the better ones that you find at department stores? The former fall apart, but I've had great luck with the latter. One pair going on 5 years old now...

Filson stuff is fantastic, but I wouldn't invest in certain things they make, especially for riding.

My personal favorites are my Under the Weather pants, though I do love my cutoff BDU pants quite dearly. They hold up extremely well and are comfortable and very functional.