I had my second one a few weeks ago - removed 3 tiny benign polyps, due back in 3 years.
My PCP is now recommending people in their 40s have one to serve as a baseline. Essentially the test is looking for changes. If you have your first one at say 55, you are already in the risky age range, and they feel not so well prepared if they don't have a previous result to compare it to.
I've had two different preps (same docs!!), and Mrs. Road Fan has had three still different ones, and none were really too onerous. Irritation is the major issue.
Pain in the procedure? Who knows, I was out cold due to the anaesthetic.
Road Fan