There's various opinions and instructions out there on this. Some surgeons are more conservative and take a why take a risk approach, others recommend it for just a few years. Mine recommends it for dental procedures, but not colonoscopies, unless there are polyps being removed. When I specifically asked my surgeon about the colonoscopy, he said there was so much bacteria there that no antibiotic would cover it all, so no, for a routine exam. Pap smears and such I've never heard it recommended for, probably because of the type of bacteria present, a cleaner environment, if you will. The mouth is a bacteria haven. I have to say, I'm more apt to get annual cleanings than every six months. I know about obsessing. A couple months back, I went to the emergency room because I was peeing red and was afraid to wait until morning for fear I had blood in the urine indicating a bladder infection and wanted antibiotics sooner that later. Turned out to be the beets I'd eaten the night before!