I'm not sure I have ever completed a system - I did the Original FIRM 90 Day rotation a couple of times back when I still had most of the original FIRMs.
Seems like I can never get through a whole system before buying something new and moving on. Usually I keep the system for a while and then end up sellling it.
I have done all but one of the FIRM Express 30 Day Slimdown but now I just got a bunch of new workouts so I'm not sure if I'll get back to FE or not.
My plan is to continue doing a couple of them every week but right now the lure of new workouts is keeping me from doing the one I had scheduled for this weekend