It's all on you - hey you can wing it. The first cleanse I did, my wirst days were 3-4, then 5 was ok, then 6 went on a run, felt good! A lot of people say finish on a high rather than a low, probably more for psychological purposes, associating a good feeling with the cleanse. The only thing I recommend is that whatever you do make sure you'll be happy with it and make sure you break correctly.
I'm on evening day 4 and I don't feel any detox symptoms at all... just this disgusting tongue. That's pretty perfect - just enough so I know good stuff is happening. Man, was I happy to get home from work today and brush my tongue!!!