I don't mind them but I think they make the most sense in games with survival elements where resource managing is a key element. I'm not a fan of the kind of implementation where you don't actually have to worry about losing your gear because they last long and it's easy to repair them. Why have a durability system when it adds nothing to the game but a break from your quest to make your sword great again?
Good use of a durability system is letting the player find really good gear early on and thus provide the option to take on a limited amount of enemies or quests that's above the player's current level, without breaking the overall game balance.








