The first time I did STS I did the 5.5 month rotation and loved it. Like FitMommy said, it gives you a chance to really figure out what weights you need the first time through. I have also done a 3 month rotation. I don't know that I got better results either way, it is more what you want to commit to I think. Right now I am doing it another STS rotation. I am almost to the end of Meso 3, then I am going to go back to Meso 2, and then Meso 1, but going to do the discs in reverse, so I at the end of Meso 3 I will go back to disc #24 and count down to #1 from there. I have not done this before, and can't wait to see how it goes! STS is great no matter how you do it!