I've never gotten past the first week. I just find it really monotonous. By that point I usually end up with some kind of joint pain anyway from doing too much too fast because I'm going to make sure I get immediate results. If you're not already fairly active so your body is used to it, don't think you can throw yourself into this hardcore plus a bunch of added cardio or something everyday. Ease into it is my advice and hopefully you won't get too bored with it too quickly.