Agree!
I had braces for 4 years as a child now I have them again for 1 year, until double jaw surgery ...any longer prior to surgery and I would have changed Orthodontists, lol.
The timeframe should be less, my Ortho said the crowding issues that were resolved and work completed should account for something. Even though there had been movement and my teeth were not 100% stable, they were definitely better than previous to any orthodontics and I had headgear and camouflage (which didn't work).