I did the Master's Cleanse for 20 days and then switched to vegetable juices for the remaining 10 for a total of 30 days because my stomach basically stopped digesting food or at least, stopped doing it without massive amounts of pain for me, no matter what I ate. I know now that my digestion has been effed up by my shit diet these last ten years, but at the time...I was desperate. I used to believe in cleansing a lot more than I do now, however, giving my digestion a rest really seemed to work...for a while, until I went back to eating Ramen cause I was broke. It happened again, and I caught it before it got to the point it was before and am now trying to fix it with Primal eating.
During the day, I felt great while on the cleanse...even just drinking half of what was recommended (cause yeah...the gag factor starts to go up quickly with both the drink and the salt water flush) allowed me to maintain my daily activities. However, night time was AWFUL. I never was really all that convinced that I was doing the right thing because I never could find any real evidence to back up the health claims of the cleanse...so there were times when I thought I was going absolutely nuts and wondering if I was doing more damage to my body. I did it cause I needed to, but I'd never recommend it to anyone else.