It should be ran daily, there is no need to take days off...
There are studies back to the 90's showing the benefits on it for six months and a year... its all about your bloodwork and body response but most tolerate it quite well.. its not something you want to use if you are going low carb but as i said, most do quite well.. to get full benefits , like the fat loss and longer term anti aging etc. you need to go at least six months on it.. some will opt for just 3 but that is personal preference to you and how you respond to it