Don’t want your teeth to shift. The orthodontist works to his definition of a completed case not the definition of the last ortho or not to the definition of the patient. Obviously they have to balance a satisfied patient with their end goal. You see a small gap he sees maybe 20 other things that need to be corrected to have you treated at the standard of care he lives by. I’m not an ortho I’m a pediatric dentist but that’s how I see it.