Ive rolled many times and I still usually only take one pill...two at the most. But it also kinda depends on what kind you get cause some aren't as good as others and you may need more.
IMO if one pill does not equal one dose (dose=whatever it takes to get you feeling good) then it's a shitty pill and you should stay away from them. some people are bigger, have different tolerance's (can you have a natural tolerance for mdma? not sure) so I would say 2-3 should be a persons max for a night.