How does one "waste" a limit break?

[TSLsmokey]

LB is like uber in TF2. Use it early, use it often. The only wasted LB is the one you hold on to when you could have used it to clear the fight.

Or one that completely misses the boss. Yeah that happened to me multiple times. That bard just figured that he didn't want to move after activating it and the boss moved out of the way a good amount of time before it fired off.