if you want to get technical...how do you stash your bud? if you keep it in bag it is probly not as potent as when you first got it...and do you normally smoke shwag or are you talking about quality herb? sometimes i wonder if the typical shwag i see is even worth smoking or if it is even capable of getting you high without using massive quantities: which is not only incredibly bad for your health but also produces a terrible headache in my experience. any way you cut it, the research is there: the "tolerance" u r experiencing is probably created by your mind...just like the feeling of being drunk off nonalcoholic beer when you believe it has alcohol in it.