you, and only you, decide how many flushes to do. some people say to flush until your liver is completely clean of stones - which i've heard in some cases happens in 6 or 7 flushes - others do upwards in the twenties before they stop getting stones.
but... there's no rule that says you have to flush until all the stones are gone. some people flush a few times, feel a tremendous lightening of symptoms, and don't feel the need flush again.
flushes do tend to get easier with repetition, as far as recovery time goes, and many people go to work the next day, once they get some experience at this.