Ive found that I am back to wet behind the ears state after about two months of not smoking. I get a noticible difference in tolerance after just the first week clean, and usually that is enough to make things nice again right there.

Three months, should most likely be enough that you have effectively hit the reset button, but it really depends on alot of things, such as body weight, how much you used to smoke, and what kind of bud you smoked.