Yay! I like taking answers that I haven't already covered! 8D
Well, understand that armor provides Armor Class to its user, not Hardness.
Hardness applies to any item that is in danger of being damaged. Hardening increases an item's protection (if any) so if a bad thing happens to your favorite maul (like Glider smashing it in half with his Improved Sunder Feat!) or if you're trying to reinforce that wooden door the ogres are trying to break down to get to you, Hardening permanently decreases how much damage that item takes every time it is damaged.
At Luna's level, Hardening can make that wooden door stronger than stone (to iron-level hardness).
Hardening does not affect living things in any way.
Well, understand that armor provides Armor Class to its user, not Hardness.
Hardness applies to any item that is in danger of being damaged. Hardening increases an item's protection (if any) so if a bad thing happens to your favorite maul (like Glider smashing it in half with his Improved Sunder Feat!) or if you're trying to reinforce that wooden door the ogres are trying to break down to get to you, Hardening permanently decreases how much damage that item takes every time it is damaged.
At Luna's level, Hardening can make that wooden door stronger than stone (to iron-level hardness).
Hardening does not affect living things in any way.