Every 6 mo. To see the build-up they scrape off at 6 mo, I would hate to see my teeth without cleaning in a few years...and I brush at least 2 times a day. I have dental ins so 2 times a year and it is free...no reason not to.
I brush 3 times a day. Morning, lunch time and before I go to bed. Flossing at night also.
Never having cavities before, and eating healthy, it's worked so far.
But I would like to start seeing a dentist again. It's been a very very long time.