|Limit Breaks are special abilities unique to FFd20 that all base and prestige classes get at 1st level. To activate a limit break, most require a standard action (though some limit breaks allow swift actions to be used) and you can only activate a limit break while your health (or the health of your animal companion, automaton, bone commander, etc.) is 50% or less. All limit breaks are considered supernatural (Su) abilities unless stated otherwise. In addition, a limit break cannot be activated while another limit break is in effect (like some that have durations).
At 1st level, you get 1 limit break usage per day, and every 4 levels thereafter (2 levels for prestige classes), you gain an additional limit break usage.