1 bowl does me good, and i've also been smoking for 5 years.
However when i first started smoking, I would just keep smokin like non stop, because I kept thinkin there would be some kinda bigger better high. Its wasteful to smoke alot in one sitting, because you can only get so high. Also somthing else i've noticed is, I have almost no tolerance as long as i only do one bowl everytime i smoke, but if i smoke more than 1 bowl, I have to smoke more and more each time i smoke to get the same effects... untill eventually I can hardly get high at all unless i take a break.