Board Thread:Dark Souls/@comment-174.23.142.74-20140614030633/@comment-3492791-20140614034748

You need to periodically repair your weapons and armor. To do this you need to purchase the Repairbox from the Undead Male Merchant. If a weapon reaches 1/3 its max durability it will become "at risk", where it will do only 70% its damage. If durability reaches 0, it becomes "broken", where it does only 35% its damage.

After getting the repairbox, you need to go to a bonefire and select the new "Repair Equipment" option. You can then repair any damaged equipment in exchange for souls.