A lot of folks have posted the general wisdom - which I don't disagree with - especially for anyone new to the activity. However, speaking from many years of personal experience, it really depends on what you are using and how much, and each person's unique recovery dynamics. With AAS, I started big and bold and have since scaled back a lot. A lot of guys wouldn't bother using my doses, but as primarily a swimmer and runner with a good diet as well as quickly recovering testicles and no history or tendency for some of the common side effects, I have found over time that it is flexible. If you go big with a cycle and want to grow a lot, shutdown will be worse and you need to responsibly recover. If you go light and your overall lifestyle and genetics proves it can support it, then time off becomes more relative. You can only find that out with years of experience.