I've always wondered how casters and other mana-using DPS keep their mana up over the span of 4-5 minute raid boss fights?
Do they just downrank spells or what? Do they have to chug potions along with using class abilities like evocate or life tap? With vanilla spell costs, I'm having a hard time imagining a Mage sustaining 5 minutes of casting. Only way I can see it happening is by downranking to just the right rank where you can spam it nonstop with potion+evocate+mana gem on cooldown.
Though, I'm not entirely sure which caster DPS are even raid-viable in the first place, outside of mage and warlock.