Item repair

Item Repair is a feature added in Beta 1.9 Pre-release 3 which allows players to repair damaged Tools, Armor, or other items with durability by combining them on a Crafting grid. Two items of the same type and material can be placed anywhere on the crafting grid, and the result is a single repaired item. The repaired item will have usage points equal to the sum of the old items' usage points plus a 'repair bonus' of 10% of the item's maximum uses, up to a limit of the maximum durability for that item.

Even if both items were enchanted with the exact same enchantments, the repaired object will always be unenchanted. The player can always re-enchant it again later. Hence, given the current (as of version 1.2.5) random enchantment system, using a 'junk' item in a repair may sometimes be useful for removing an unwanted enchantment from an item prior to trying to enchant it again.

Repairing gives a slight benefit in conserving inventory space, as it combines two non-stackable objects into one, and the ~10% 'repair bonus' allows you to get slightly more total uses out of tools, which helps eke out resources a little further.

Tools made of different materials (for example, a wood and a stone pickaxe) cannot be combined.

Formula for Uses Restored
The formula for determining how many uses a repaired item will have restored to it is as follows:

min( floor( Item A uses + Item B uses + (Max uses / 10) ), Max uses)

('floor' means round down to the nearest integer, 'min(a,b)' means whichever of a or b is smallest.)

Example: Two stone axes have 10 and 45 uses. A newly-crafted stone axe would have 132 uses.


 * 10 + 45 + 132/10 = 55 + 13.2 = 68

This algorithm gives the greatest benefit when two tools combined have an average durability of no more than 45% of the maximum, but as long as that is the case, the benefit is the same if the two tools have 1% durability each remaining, or 45% and 45%, or 89% and 1% and so on.

When repairing items, the order they are combined in does not matter. For the maximum benefit, merely try to use all items in a repair before they finally break, and avoid combining items whose average durability is more than about 45%.