it's not exactly an addicting drug, or a fun one for that matter. one of the most intense i've tried though, any deliriant is.
to prevent tolerance i'd stick to once every week maybe. actually maybe every 2.
just remember higher doses don't mean a better trip, they could end you up in not very nice places, setting however is important. i find that fighting the sleep by staying up late at night while on it made the hallucinations much more vivid, whereas during daytime i'd only see ripples on the walls and see-through spiders occasionally.