Talk:Avatar Parts
This should probably be included somewhere.
I didn't know exactly how they work so I searched the forum to find this tidbit:
Perks System: certain avatar parts now possess perks, which can boost your effectiveness in battle or increase the appearance rate enemies, items, and even raid bosses. So far the perks in the game are: skill perk, critical hit perk, rare enemy perk, item drop perk, raid boss perk, and raid boss Ω perk. You can check what perks your clothes may already have by pressing the perk button on the Outfits screen, as some previous avatar parts have been given perks.