Unbreaking

Unbreaking is an enchantment that gives a chance for an item to avoid durability reduction when it is used, effectively increasing the item's durability.

Unbreakable
Unbreakable is a unobtainable enchant in survival, but in creative it is, the enchant does what you hear; unbreakable, the item enchanted by this enchant will never be breakable.

Obtaining
Unbreaking I, Unbreaking II, and Unbreaking III can be acquired using an enchanting table and by fishing, in dungeon chests and by trading with a librarian villager.

Usage
For most items, there is a $$\frac{100}{level+1} %$$ chance that using the item reduces durability. On average, tools last $$level+1$$ times as long. For armor, there is a $$\left( 60 + \frac{40}{level + 1} \right) %$$ chance a use reduces durability, meaning each durability hit against Unbreaking armor has a ~20%/27%/30% chance of being ignored. On average, armor lasts ~25%/36%/43% longer.

When durability is reduced by multiple points, as when hooking a mob with fishing rods or getting blown up with TNT, Unbreaking is applied for each point of reduction.

ID