It's tough to answer because detoxing symptoms varies widely from person to person, and even from cleanse to cleanse in the same person.
I've always worked during my cleanses, but for the first one, I had to call in sick on day 3 because I had such a terrible headache and flu-like symptoms. Other cleanses have varied. This one, which is somewhere around my tenth, I haven't taken one day off and am actually exercising (highly recommended during a cleanse, but something I never really did before).