you really need to flush until ALL stones are gone if you want your body to be able to heal itself. and you need to detoxify the liver as well. i don't think anyone has managed to clean their liver in a flush or two. and yes some people seriously have to do 10-20 flushes to get everything out. there is nothing quick or easy about the process, of course we could live our whole lives feeling sick and nobody wants that. so the goal is, free your liver entirely of these stones.
as far as flushing frequency goes, it's usually best to flush every 2 weeks to every month(as far as i know). don't flush too soon, you need to wait for more stones to move forward so every two weeks would be the minimum. and yes, it can be frustrating wondering if there's an end, but somewhere around the 2000 stone mark i could sleep again. that was enough for me to keep going.