Durability is a value which represents the number of uses remaining of a tool, weapon, or armor. Only items that have a Quality level use the Durability stat.
Max Durability of an item is determined by the Quality level of the item. Inspecting an item's stats in your inventory will display its Max Durability.
Items that have the Durability stat will have a colored bar located in the lower portion of the item's icon when viewed on the Tool Belt or in the Character Inventory. When this bar is full, the item is at Max Durability. As an item loses Durability, its Durability bar starts to shrink. The colored bar length reflects the percentage of Durability the item has remaining, and the color of the bar is determined by the Quality level of the item.
Effects of Durability
Weapons and Tools typically lose 1 point of Durability with each use. All equipped Armor will lose 1 point of Durability each time the player's character is hit by an enemy. The sale value of an item is reduced proportionate to its Durability loss. Otherwise, all items are fully functional while the Durability is above zero. When an item's Durability reaches zero, the item ceases to function. Durability is used slightly differently for different categories of items.
Most tools use the Durability stat. Each use of the tool reduces its Durability by the Degradation per Use stat of the tool, which as of A18 is set to 1 for all Tools. When the Durability of the tool reaches zero, it is no longer usable.
Most weapons use the Durability stat. Each use of the weapon reduces its Durability by the Degradation per Use stat of the weapon, which as of A18 is set to 1 for all Weapons. When the Durability of the weapon reaches zero, it is no longer usable.
Most armors use the Durability stat. As you take damage, all of the armor you are wearing will have their Durability reduced by 1 point. Armor that has its Durability reduced to zero will no longer provide any protection.
All vehicles use the Durability stat. Vehicles do not have their Durability reduced with normal riding of the vehicle. Instead, Durability is reduced when the vehicle is being driven and collides with certain items in the environment. Attacking a vehicle also will cause damage to its Durability. When the Durability of the vehicle reaches zero, the vehicle will explode and is destroyed in the process.
Most items can be repaired, which results in the item's Durability being restored back to its Max Durability. Some items cannot be repaired.