You should always go to the dentist every six months.
John has a very busy day including a trip to his biannual dentist appointment and a night out at the movies.
John wants to clear up his schedule a bit.
John decides to cancel his night out at the movies.
John decides to cancel his dentist appointment and go some other time.
John gets a thorough cleaning at the dentist and his teeth remain healthy and strong.
John ends up with several cavities when he finally reschedules his appointment.