Originally Posted by Krooow
Actually, you don't automatically lose max durability each time you repair your equipments. I believe it's around 50% chance of either lowering its max durability or restoring its durability(from 0/100 to 100/100).
For upgrading, the equipment's durability(not max dura) will only drop to 0 if you failed on your attempt.
Yes, that sounds about right.
You don't really have to worry about durability really. It won't go down that fast, so it's actually not too big a deal.
... Well, says me. Since I hardly lose durability in weapons and armors... Not sure about others.