Personally, I have chosen to do the 3 phases of STS once per year. I start it each January and do it until the end of March. This is my third year and I love it. To me, it is the BEST workout available, especially for changing body composition and building muscular endurance, definition and strength. But, even though it is my all time fav, I do other Cathe workouts between April and the following January. This allows me to focus on other goals, change things up for variety, and experience the fun and benefits of Cathe's other programs. Then I return fresh to STS the following year with excitement and enthusiasm. I have found XTrain to be a great follow-up program. And I am now finding Strong and Sweaty to be a super complement to STS as well. If you are focusing on muscular conditioning (and as an STS user, I am guessing you are), then Pyramid Upper and Lower Body, Gym Styles, 4 Day Split and Slow and Heavy may be of interest to you as they also are split routines that motivate you to give it your all. I enjoy making a yearly plan so that I can be sure to fit them all in eventually. You may like to explore some of Cathe's rotations that focus on the goals you have set for yourself. So many fun ways to keep the body challenged!