I just finished up my Invisalign treatment. I still wear the retainer at night and will probably have to for the rest of my life.
My dentist had me on Invisalign Express, which is for about 6 months, but I have previously had braces as a teen and they had shifted since then, so I didn't have to do any major orthodontia. I am 43.
As a person who has now done both traditional braces and the invisaligns I greatly prefer the latter. Much more comfortable, I would have a bit of soreness for about two days with each new set. I got a new set every two weeks. The retainer looks just like a thicker set of Invisaligns and I wear them only at night. I remember with traditional braces my mouth would be sore for almost a week after each tightening. You also take them off for eating so you can eat things like corn on the cob and popcorn, which are tricky with traditional braces.
They also would dry out my mouth. I found myself drinking a whole lot of water, which is the only thing you can drink with them in. I am telling you, it really cut down on my coffee drinking in the morning as I couldn't nurse a cup or three all morning while I worked. I had to wear my aligners 22 out of 24 hours. You also get used to carrying a toothbrush with you everywhere in case you want to eat out and then go do something, because you need to brush and floss every time before putting them back in (I always brushed, but would wait until I got home to floss). A side benefit (for me anyway) was that I lost a few pounds because this really cuts down on random snacking!
One thing I didn't like about Invisaligns was the price! they are expensive and my dental plan doesn't cover adult orthodontia!
Jen