In extreme trials and savage raids, there are things like enrage timers where you need a certain amount of rDPS to successfully clear the fight. For example, Sigmascape Savage V3.0 (O7S) requires ~29,500 rDPS to clear the enrage. Some 24-mans also have enrages, but they’re more lenient than Extremes/Savage/Ultimate.

Dungeons generally don’t have these sort of enrages, or if they do, they’re extremely lenient.