I had braces for almost 3 years. For the first year or so, they hurt for days every time I had them tightened. It wasn't as bad after my teeth were straight and the "adjustments" were less drastic. I have a few tips about braces:
1. Don't eat popcorn...or caramels, or chewing gum, or whole fruits. Or nuts, seeds or hard candies. In other words, don't eat anything that could damage the brackets and/or get stuck in your teeth.
2. Don't have your mouth open while you rub your face on a piece of fabric (drying yourself off with a towel, etc.). Trust me on this one.
3. Don't set your appointments to have your braces tightened to be right before an important event or holiday.
4. Be very careful brushing your teeth.
5. Once you get your retainer, wear it!