In fact, my own experience is that two weeks does the trick much better than one, and the difference is enough to make the wait worth it. Not only that, the practice of going half the month without guarantees no serious addiction/WD issues. Three days? No. A week? You'll get a rush, but likely not quite what you're hoping for. I agree with the above posters recommending one week, but I submit to you that two weeks is the best practice in the end, because this dosing schedule will be very very effective at preventing any significant increase in tolerance over a long period of time. Best of luck.