Mending

Mending is a rare general-purpose enchantment in Minecraft 1.21. Mending repairs your gear automatically by diverting experience orbs into durability: whenever you collect XP while holding or wearing a Mending item, the orbs fix it instead of filling your XP bar.

There is only one level to it, so nothing needs upgrading — the instant it goes on almost any piece of gear you have the whole effect (Each XP orb repairs 2 durability points on a random mending item).

Mending exists at a single level only, so there is no scaling curve to climb — applying it to your gear hands you the complete effect in one step, with no Mending II to chase.

It has a single level. Each absorbed XP point restores 2 durability to a damaged Mending item; if every Mending item you carry is already full, the experience flows normally to your level bar. Crucially, it cannot share a bow with Infinity.

Mending is about as universal as enchantments come — it goes on sword, pickaxe, axe, shovel, hoe, bow, crossbow, trident, fishing rod, helmet, chestplate, leggings, boots, elytra and mace, which is to say nearly every durable item you own can run it, making it a default consideration on any new piece of gear.

Mending cannot share an item with Infinity. Because of that single conflict you have to pick either Mending or Infinity for any given item — never both.

Mending is a treasure enchantment, which means an enchanting table will never produce it. Your only routes are villager trading, loot chest, fishing and raid drops, after which you combine the book onto your gear with an anvil.