As a DPS, I observe what my fellow party members can do. (And since I'm currently leveling up Bard, even more so.) If I notice that the tank had difficulty with me going pants-on-head crazy with Flares and AOEs, then I hold back. If the tank and healer can handle it, then I'm like "KIIIIIIIIIIIIIIIIIIILLROOOOOOOOOOOOOOOOOOOOY STOOOOOOOOOOOOOOOOOOOOOOONESKIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIN!" Better safe than sorry, after all.