Actually, I just turned 65. I had one of these exams in 2003 and was told to get another one in 10 years. It's a routine exam and I'm not expecting any problems.
With the ability to control colon cancer, everyone should consider a colonoscopy at the proper age your doctor chooses. They use general anesthesia and you don't feel a thing. An ounce of prevention is worth a lot of piece of mind. And it could save your life. Just like prostate exams..... they ain't fun, but they work.
TIP: While waiting for the prep to work, don't sit in a comfy chair that's hard to get out of in a hurry.