I've noticed that a lot of people seem to do a rotation of upper body for (what I consider a long time,) 10 weeks or so. I tend to get bored and find myself using 2 or 3 tapes for 3-4 weeks then having to change. My question being; is there a reason why one should go that long on a rotation? Also, am I the only one that doesn't care much for working the back? If I'm short on time this is always the body part that I don't care if I miss.