Some say no more after 75 I guess some say 70. But it does make a difference your history and lets say you reach 75 but have not had one for 8 years....rather be safe and have one more while still easy (relatively) to do prep. This will be my third with no history of polyps. Doctor ordering this at Mayo is not in the GI department and is fine with me using any of the preps. It is routine. Just seeing if anyone had a story about taking xxx and not complete clean out? I also think it might be more difficult in terms of electrolytes etc. the older you are.