I have to also congratulate you on being "prescription free" at your, or really any age, these days.
I had a doctor who discounted the PSA test some years ago and relied mostly on his digital test for diagnosis. However, I always insisted on the PSA. One year, I got an elevated number and was stressed about it. The doctor said the digital was normal, but he was going to play it safe. He ordered a biopsy and I went to see Dr. Ouch for the procedure. Now, don't get me wrong, I would gladly undergo this procedure again if it would save my life, but this was indeed a "sobering experience" to me.
As for the colonoscopy, this test has allowed me to sleep easy more than once. How many other tests or procedures are we offered in life where the cause/potential cause of cancer can be removed instantly? I've had one close call and that is part of the reason the Livestrong band stays where it is!