How Long After Invisalign Do I Need a Retainer?

If you would like your teeth to stay perfect after you finish Invisalign, a properly fitting retainer is essential. You don't have to wear the retainer all of the time but at least 3 to 4 nights per week. If you ever see your teeth shifting or space re-opening, then you can increase to 6-7 nights per week. Also, if you do not like wearing the retainer while you sleep, you can wear it during the day instead for around 6-8 hours.
Retainers are like orthodontic insurance. If you wear a properly fitting retainer every night, your teeth will not shift! If you don't wear a retainer, it is like throwing the cards up in the air. You don't know how they will land. For some people (the lucky ones), teeth don't shift; but for a lot of people, the teeth will shift over time. 
I still wear a retainer every night. Yes, I have to because I'm an orthodontist. But even if I wasn't an orthodontist, I like my smile and want it stay like this for the rest of my life, and retainers are the answer.

Hello,
I love that you are looking at all the commitments you need to make before you start treatment. A fun way to say it is “you only have to wear your retainer for as long as you want straight teeth”. But joking aside, teeth shift all your life. Yes, retainers are a life-time commitment. 
For the bottom teeth, sometimes there is an option of placing a fixed retainer that is glued behind your teeth, then you would not have to worry about remembering to wear a retainer. But on the top, you have to wear your retainer at nights indefinitely. 
Best,
Dr Sepi Torkan