My 1st and 5th flushes yielded the best results. The 2nd was four days after the first and all the others have been two weeks apart. I onlyh passed a very few stones on the 3rd and 4th flushes. I had a lot of discomfort and problems after the 4th flush but at the 5th flush I passed 60+ large stones and I am feeling a lot better. I will see how I feel and flush when I feel the need. Maybe 2, 3 or 4 weeks but definitely at 4 if the problems do not come back in the meantime.