Durability (Fallout 76)

Equipment condition returns in Fallout 76 from Fallout 3 and Fallout: New Vegas; however, unlike in previous games, armor and weapons can be repaired using junk and crafting components at an armor workbench or weapons workbench. Alternatively, equipment can also be repaired without a workbench by using a repair kit or improved repair kit. As equipment condition degrades, weapons will continue to do the same damage and armor will provide the same protection. When the equipment's durability runs out completely, though, it will be broken and cannot be equipped again until it has been repaired.

The condition of equipment is also tied to its trade value in caps. As equipment loses durability, its value goes down until the cap value reaches zero when the item is broken. Items with better than 100% condition do not gain any additional caps value. The Legendary scrip value is not influenced by item condition.

Weapon condition
Weapon condition degrades when any of the projectiles/pellets of your attack successfully land on one or more enemies or objects which can be damaged, causing an estimated 0.25 - 1% loss in the used weapon's durability per attack.
 * Attacks which hit the environment or objects with no health/durability or which do not hit anything at all, will not count toward condition degradation.
 * Ranged weapon durability loss can occur when melee bashing with your gun, but otherwise it is per shot.
 * Weapons cannot be used once they break but remain equipped, forcing you to equip a new weapon or use your fists. A broken weapon cannot be reequipped until it's repaired.

Note: Prior to the Patch 1.5.1.26, condition drain would occur per projectile/pellet and per enemy damaged, more quickly degrading the condition of shotguns, explosive launchers, weapons with beam splitters and shotgun-style mods, and weapons with the Legendary Explosive or Two Shot effects, among others.

Armor condition
Armor condition degrades when you receive health damage from attacks or environmental dangers such as explosions. The amount of durability lost on worn equipment depends on how much damage is received and takes into account damage reduction from equipment, effects, consumables and perks.
 * Armor remains equipped when it breaks, but no longer provides damage resistances. This allows for mods and legendary effects to continue functioning until the armor is unequipped, but the armor will need to be repaired in order to provide damage reduction or to make it equippable again if you take the armor off.
 * Unlike regular armor pieces, when a piece of your power armor breaks it will be unequipped from the power armor chassis and moved to your inventory. This has an influence on set bonuses like the carry weight bonus from Excavator power armor, which is only in effect when a complete set is worn, as well as the inherent damage reduction (7% per worn piece) and radiation reduction (15% per worn piece) of power armor. It also has a negative influence on carry weight, since power armor pieces on a power armor chassis have no weight.
 * Hazmat suits, which provide no damage resistance, suffer no condition degradation whereas the otherwise similar Chinese Stealth Armor provides damage and energy resistance and degrades when hit.