I think it took me about six before I passed the mother lode of about 40 beautiful, prune sized and shaped, jade green stones. My health changed for the better in a permanent way after that, and I never saw that kind of flush again.
I still do annual maintenance flushes. I am doing a 10 day Master-Cleanse now, and will do a second flush in this series after the break.
What a cheap, effective, simple thing to do for yourself! Keep flushing until you know you're done. Give a nice break between flushes, and keep after it. Well worth the time and effort!