unless you're going on a trip with your parents or something, anytime is good. During the abstinence period, find new and different things to do, otherwise it'll be hard not to blaze again. Take up a new hobby, start a new exercise regimen, hang out with family more, anything that is a sufficient and worthy distraction from the normal contentment of gettin blazed. When you start up again, smoke smallish amounts and put some time in between smoke sessions. This will help you not hit a plateau again. Have as many straight hours as you do stoned hours. You will appreciate MJ much more