Durability for both weapons and armor decrease upon usage in Godwars. A 0 durability item will not be destroyed or be unequipped however it will have no effect(IE your follower will use their fists if your weapon is 0 durability).

Cost of repairs varies based upon material of the item, level and how much is missing. By using the Auto-Repair Threshold option, you can have the game keep your items maintained at a working state by using your horded currency anytime an active roster check is made.