Equipment - gear, weapons, armor - have durability between 1 and 5; the higher the sturdier. Glass and cloth have 1 durability, wood and bone 2-3, metal or mythical 3+.

When an item is used as part of a check (weapon for attack, armor for defense) it might take sundering damage. Rolling a critical failure or suffering from an enemy’s critical success reduces the item’s durability by 1. Once at 0 durability, the item breaks.

Only repairs can restore durability. Shields can trade HP damage for sundering damage, preventing HP damage at the expense of the item’s durability. The PC must declare that they are sacrificing their shield in this way.