From what I have read if you have a highly acidic or mucous forming diet, they can form daily, but some have been lodged in the intestines for years. I am no expert. I really was shocked when I passed them, I was very adventurous and washed them off, and found they were as thick as a tire! I assume whatever THAT was had been around for some time. In a month I passed 12 feet, and I have just ordered Oxypowder which I am going to do with enemas to help get the rest of the "gunk" out. I also am preparing for a liver flush. Good luck on your journey!!