Custom Armor Durability is a module provided in Cartographer. It applies a revised durability format to Armor that makes armor last much longer than in vanilla.

Custom Armor Durability is not currently provided for Minecraft Version 1.19.3.

Revised Formula

When the player takes damage while using this module and wearing armor, all armor pieces will take damage, just like in traditional Minecraft.

All armor pieces will take 1 damage whenever they block damage (same conditions as vanilla).

Additional Balance Drain

To make all armor drain at a more equal rate, armor pieces that are not helmets have a chance to take additional damage.

Chestplates have a 40% chance to take an additional point of damage, Leggings have a 33% chance to take an additional point of damage, and Boots have a 16% chance to take an additional point of damage.

(These values directly rate to the proportional additional durability the different armor piece has with respect to helmets in its tier)

Overhit Durability Drain

Additionally, if the damage the player would take exceeds their armor stat (i.e the player takes 7 damage while having 4 armor points) all armor pieces the player is using suffer 1 additional point of damage.

Unbreaking

Unbreaking unlike traditional Unbreaking on Armor has a chance to negate all damage dealt to the armor piece, rather than applying individually per point.

The chance is also altered, with a revised formula:

Each level of Unbreaking provides the armor piece with a Level/Level+3 Chance to negate the damage dealt.

This means armor has a 25% / 40% / 50% / 57% / 62.5% (for levels 1-5) chance to not take any damage when it has Unbreaking. (Levels beyond 5 work, this is just to demonstrate the revised formula.)