Breaking equipment

When you roll a natural 1 on a weapon attack, after dealing damage, reduce one of that weapon's damage dice by 1 size.

d12 > d10 > d8 > d6 > d4 > 1 > broken

When suffering a critical hit, reduce the AC your armor gives you by -1.

Breaking equipment on purpouse
Sometimes, winning a battle is more important than keeping your gear intact. Sometimes, you have to take everything your weapon has left and use it.

You may choose to attack with disadvantage: if the attack hits the hit is automatically a critical hit. Then, reduce that weapon's damage die by two steps.

When desperate, you may rather safe your hide than your gear. If you are wearing armor, you may use your reaction choose to give yourself resistance to nonmagical damage. After doing so, reduce that armor's AC value by -1.

If you are wearing a shield you may use this reaction to ignore the damage altogether. After doing so, the shield is splintered or broken beyond use.

These options are not available for unarmed attacks, natural armor or magical equipment.

Repairing Equipment
Characters proficient with the appropriate tools can repair broken equipment. Kegold also offers this service.