Two enchantments decide how long your gear lasts, and most players understand exactly one of them. Unbreaking is the obvious one. Mending is the one that changes the game, and the interaction between them is where the actual strategy lives.
Unbreaking does not do what it says
Unbreaking does not make an item more durable. It gives each use a chance to consume no durability at all. At Unbreaking III on a tool, roughly three uses out of four cost a point and one out of four is free, which works out to about four times the effective lifespan.
Armour follows a different formula and benefits more per level than tools do. That is deliberate: armour takes durability damage on a completely different schedule, tied to incoming damage rather than to actions.
The practical takeaway is that Unbreaking III is not three times better than Unbreaking I. The returns are multiplicative and front-loaded, and the jump from none to one is the largest single improvement you will make.
Mending changes the category
Mending redirects experience orbs into repairing whatever damaged gear you are wearing or holding, at a fixed rate of durability per experience point. While any of your Mending gear is damaged, you collect no levels – the XP goes into repair instead.
This turns durability from a resource you spend into a tap you keep topped up. A Mending pickaxe used in a world where you routinely kill mobs or run a farm will never break, not because it is durable but because it is being continuously repaired.
The catch that surprises people: Mending repairs the damaged item, and if several are damaged the XP is split among them. Wearing a full set of damaged Mending armour while holding a damaged Mending tool means each piece repairs slowly. Repair one thing at a time if you are in a hurry.
Why they stack rather than compete
The instinct is to treat these as alternatives – one makes gear last, the other fixes it, pick one. They are strongest together, and the reason is the XP budget.
Mending’s cost is measured in experience. Unbreaking reduces how much durability you lose, which directly reduces how much experience Mending has to spend to keep you topped up. Unbreaking III on a Mending tool means the same XP income sustains four times as much work, or leaves you with surplus XP for levelling.
That surplus is the real prize. A player with Unbreaking III and Mending on their main gear can actually accumulate levels while playing normally; a player with Mending alone spends most of their XP income on upkeep. If your levels never seem to climb, this is usually why, and the XP mechanics breakdown explains where the rest of it goes.
Getting them
Mending cannot be obtained from an enchanting table. It comes from three sources: fishing, chest loot in generated structures, and villager trades.
Librarian trading is the reliable route. Cure a zombie villager for the discount, or cycle a librarian’s trades by breaking and replacing its lectern until Mending appears. This is tedious and completely deterministic, which is a better deal than it sounds. The villager trading system covers the cycling mechanic properly.
Fishing works but is slow, and an enchanted book from fishing is a random draw. It is worth doing if you have an AFK fish farm already; it is not worth building one for Mending specifically.
Unbreaking, by contrast, comes straight off an enchanting table and is one of the more common results. You will get it incidentally.
Combining costs
Adding both to one item means anvil work, and anvils accumulate a prior-work penalty that rises each time you use them on the same item. Combine in the wrong order and an item becomes “too expensive” permanently.
The rule: combine books with books first, then apply the combined book to the item once. Two books merged into one costs less overall than applying two books separately, and it leaves fewer prior-work increments on the tool. The full cost logic is in the anvil cost guide, and it is worth reading before you touch a netherite tool.
When to skip Mending
On gear you use rarely, Mending is dead weight – it competes for an enchantment slot and never gets fed. A backup sword, a decorative set, a tool used once a week: put Unbreaking on it and nothing else.
On gear used in situations where you earn no XP, Mending also does nothing. Elytra are the classic case. Flying earns no experience, so a Mending elytra is repaired only when you happen to be killing things while wearing it, which is rarely. Unbreaking III plus phantom membrane repair is the more honest answer there.
Everything else – main pickaxe, main sword, worn armour, the axe you actually use – takes both.
Images: Eldritch End and Gardens of the Dead project galleries.