I have done the Liver-Flush 4x and I know someone who has done the Hulda Clark flush 41x. Myself and this person are doing a Liver-Flush every month (following Andreas Moritz and Hulda Clark 's programs) until 3 flushes in a row are totally clear. Depending on the "issues" that are being experienced and are underlying depends on how long this will take but the determination and consistancy is what counts. I know doing LF's is a VERY impowering feeling and is EXTREMELY successful when done correctly. Listen to your body. Make sure that some sort of colon therapy/cleansing is done prior to a Liver-Flush (colonics...) That way you are really working hard to diminish the chances that stray stones are left behind.
Good luck :)