It usually takes 12 - 24 months but will vary according to how severe your case is. Failed, cancelled appointments and breakages of the braces will add to the overall treatment time.
Your teeth are likely to be tender for about 1-2 days each time the braces are adjusted. If necessary, painkillers such as the ones you would normally take for a headache may help (please read the instructions on the packet).
If the braces rub your lips or cheeks, you will be given some wax to help with this.