“Games give you a chance to excel, and if you're playing in good company you don't even mind if you lose because you had the enjoyment of the company during the course of the game.” ― Gary Gygax
Thanks guys, and yes some characters global abilities can be used only once that is why i was asking.
Global abilities that require a trigger, such as War Machine's or the global on Human Torch: "Flame On!", can only be used once per trigger.
They may still be used multiple times per turn, each use just requires a unique trigger.