[LadyLightning]

Battle Spirits, Spirit weapons (restore FP equal to 10% of damage dealt), repair
powders, Etherium subweapons, the Maintenance talent, or even a subclass with
an FP engine such as Grand Summoner or Void Assassin or Kensei or Magic
Gunner. These are all viable ways to flat-out ignore durability.

That being said, permanently losing weapons that self-repair is frankly ridiculous.
Etherium weapons should be exempt from this stipulation, on the basis that they
regain max durability each battle. Divine weapons should also be exempt, as the
way 'unbreakable' is represented mathematically in the game code is to have -1
durability.