How long a patient wears Invisalign depends on several things. First, is the state of their teeth. If they only have mild crookedness, it could be as short as six months. For more complex situations, it can take a year or more. It depends on how well the teeth shift. Secondly, they need to be sure to wear the Invisalign for the needed 22 hours a day. If they don’t, or they skip a day or two, then that will cause progress to slow down. If they do not follow the order either, then eventually a new set will need to be made. If they follow the instructions, then it will take the minimum amount of time.