My name is E.. I am 27 years old, and I had to have braces TWICE. The first time I was your son's age, maybe a little younger and by the time it got to my retainer, I was so tired of having stuff on my teeth, that I hardly ever wore it. I actually kept it in my pocket most of the time and it ending up breaking. My mom was very upset and I tried to re-assure her that although my teeth weren't perfect, they were better than they had been and I was satisfied.
My teeth DID shift. And not just a little!
In December 2004, my boyfriend asked me to marry him. I said yes and started making plans for my hair and my dress and my make-up and planning to be a beautiful bride. But when I looked in the mirror I realized I didn't want to have my wedding pictures taken with a huge gap in my teeth. I immediately went to an orthodontist (which isn't covered by insurance for adults) and went through a very expensive, painful experience in order to get my teeth straight in 8 months for my wedding.
My mother spent 2500 dollars on my teeth.
My teeth DID shift, it was NOT attractive.
10 years later I spent 3500 dollars on my teeth.
My mother now feels like the money and effort she put into my teeth was a waste.
You wouldn't know to look at it that I have a $6,000 smile. It's straight and pretty, but it doesn't look like it should have taken that much of an effort.
Like so many things when we are teenagers, retainers don't seem that important until its too late to take it back.
Please pass my message on to your son, and if he would like to email me or share ortho gripes, I will be glad to. Anytime.
Good luck!