What Mending does
When you gain experience orbs, any Mending item you are holding, wearing or that is in your inventory can absorb them to repair durability — two durability per experience point, split between eligible items. Because experience is abundant, a Mending tool or piece of armour never needs repairing or replacing.
Every way to get Mending
- Librarian villager — trade an enchanted book (reroll the lectern before trading)
- Fishing — Mending books appear in the treasure category
- Loot chests — dungeons, mineshafts, strongholds, woodland mansions, ancient cities
- Raid and other loot tables — occasionally
- Trading with other players on a server
Mending and Infinity cannot coexist
On a bow, Mending and Infinity conflict — you can have one or the other. Most players now choose Mending and carry arrows, because an Infinity bow eventually breaks while a Mending bow lasts forever. On every other item Mending is a pure upgrade.
The Right order for anvil cost
Mending is a level-I book, so applying it is cheap — but every prior anvil use on the item raises the cost of the next. Apply Mending early, or plan the whole combination order with the calculator, to keep the total below the 39-level 'Too Expensive' cap.