I bought a pair of 501s recently and they barely lasted 6 months. I do a fair bit of cycling which seemed to very quickly wear through them. I'm really not sure what to buy if I want things that last a long time now.
Levis are fashion products, not workwear. But even if they were, if you want things to last a long time then buy things made for a specific purpose. Denim products made by cycling brands are a rarity for a reason.