Cooldowns are battle mechanics in Xenoblade Chronicles X. After having used an Art, the Cooldown Time is triggered until the Art is available again. This Cooldown Time depends on the Art type and can be reduced by levelling it up. In addition, when the Art is usable again, the Secondary Cooldown can be reached by continuing to charge up this Art, and this will increase its effect. By using the Overdrive, it is possible to charge up for a third time to reach Tertiary Cooldown. Secondary and Tertiary Cooldowns are only existent when on foot, not when using a Skell.
When an Art is used, it then goes on a Cooldown Time counter. By continuing to auto-attack an enemy with the weapon tied to the art, the move can go on a second Cooldown Time counter. The effects of Secondary Cooldown depend on the Art, from increasing damage by 250% to increasing the tier of debuffs, buffs, or auras.
Keep in mind that the secondary Cooldown only charges when you are wielding the weapon tied to that art. For example: "Flame grenade" is tied to the automatic rifle. Only if you are wielding the rifle, the secondary Cooldown of "Flame grenade" will charge. If at any point you change to another weapon, the secondary Cooldown will pause and will begin from where it left if you go back to the previous weapon.
It is possible to charge for a third time to use Tertiary Cooldown if an Overdrive has been activated. Activating an Overdrive consumes 3000 TP. As the accumulated TP can be carried over to the next battle, if the party has trouble against a Boss or a Tyrant, a good strategy may be to accumulate beforehand these 3000 TP. Tertiary Cooldown grants effects similar to Secondary Cooldown, but of greater magnitude, such as a 400% increase in damage or an increase in debuff, buff, or aura tier of 2.
During Overdrive, all cooldowns are severly reduced, making arts recharge very quickly. In addtion, secondary and tertiary cooldowns fill up no matter what weapon is wield during the Overdrive.