You know, when I was flushing, at first, I hated the Epsom Salt taste and then after a few flushes, I began to like that taste and hate the olive oil. Ha Go figure!
Whn you begin to see less and less stones, you will know you are at the end. When you see no more stones, I would go ahead and do a couple more to make sure you are stone free. After that, a couple of times a year would be the "preventative maintenance."