I love that question. The biological answer is that if you start with a clean system and smoke one gram, it stays for a day, if it is still in your system, and you smoke another gram, it doubles, and will keep doubling as you continue to smoke until a maximum of about three months. This is all averaged over size and weight differences. Anything you add to your system that comes out as liquid, and you add enough that your system is overloaded, it will come out in the pee before solids and heavier compounds. It takes about three gallons 3 hours ahead of a pee test to cover it up.