Yes, you do. For the most effective outcome, the aligners must be worn for a minimum of 22 hours a day. They should only be removed to eat and brush your teeth. If you do not wear them for the required hours every day, the corrective movement of the aligners stops, and your teeth could start to move back into their former positions. Having lost your forward momentum, it can take a few days to get your smile back on track again, adding to your treatment time.