I'll check out the gear of the party, do a medium size pull at first to see how they handle it and gauge from there how I will handle the rest of the dungeon. In the newer ones this isn't as much of an issue since they gated sections behind mobs. Either way tanks get yelled at for pulling too big and the group cant handle it and its a wipe. They pull too small and party is in a hurry to do a speed run and are bored.