Verified answer

I think the "off" button causes the most damage.

Minecraft Sword Durability

Iron swords are much better for combat because of the damage they deal and their durability. If you use a diamond pick, it does less damage than a sword and also makes the durability of the pick go down 2x faster on enemies, so stick to the iron sword while in combat. Also, gold is not meant to be used for gold weapons because in real life, gold has a very low durability. Gold should be used to make powered rail, gold carrots for potions, etc