When something is about to break, the mod searches your inventory and swaps it out on the spot. It looks for an exact copy first, then falls back to the same tool type at a lower tier, then anything lower. If nothing is found, you get a chat message.
Everything is adjustable in the in-game settings screen: durability threshold, chat notifications, which item types to track. No extra mods needed, no config files. 43 languages included out of the box.
