I am three weeks into a 20 week program of 20 trays. I thought I'd provide a few thoughts to those considering Invisalign.First, it's not a "pop 'em in and forget 'em" system as they'd lead you to believe. It requires a lifestyle change. The buttons which they add to your teeth to hold them on are sharp and will scrape the inside of your mouth when you don't have tray in. They are annoying and visible to others when you talk.Next, they trays are tight and put pressure on your teeth - especially the first couple days of a new tray. When you take them out, your teeth ache a bit. I try to take them out 10-15 minutes before I eat to allow them to rest before having to chew. I wear have worn them between 16-23 hours a day so far and thy seem to be working just fine. I also drink liquids with them in -- just not dark liquids like coffee or red wine. I drink beer with them in and just rinse them out later in the day no problem. Probably not a good idea for sugary drinks.Bottom line you can't eat what you want when you want and you constantly have to plan meals and post-meal brushing. Brushing in restaurant or baseball stadium bathrooms, etc. It's annoying and the feel of them is rough the first day of each new tray. But after two weeks I have gotten into a bit of a rhythm but it's not as bad as the first week. I am hopeful that he results will be worth it.