I mostly agree with spreading it out, but I'd like to give a devil's advocate perspective: Newer character might like powers more frequently, so they can have new toys to play with and new things to do. A character with only a single ability in a big event might not feel like they can contribute much at all, and having to wait two or three months before they can get a second might be discouraging for player and character, since playing around with those is a big draw to the game.