Minecraft wiki entry for Best_enchantments_guide, associated text: The following armor enchantments cannot be combined: Protection, Projectile Protection, Blast Protection, and Fire Protection. Protection prevents half the damage that would be blocked by the other three. Protection is better, but there are sometimes other factors you should take into account. If you fall often in lava, it would be better to put Fire Protection on your armor. If you die often from creeper explosions, put Blast Protection armor on.