Currently what we have is a chat popup, which is great. If you’re actively looking at the screen, or you’ve got the hidden option of having your chat window open constantly you might notice before your weapon/armor breaks. Also if you have your backpack open, meaning you aren’t looking at the action bar because that doesn’t show damage, you might see the item in question turn red, again neat.
But if you’re planning on being in the south desert for a half hour watching cartoons mining ores neither of those options are going to help you.
If we could get an audible ping when the weapon turns red, or a little buzz for those on mobile, or even a red screen flash or a floating text pop up alert whenever something loses durability while it’s under 20%.