I'd suggest you get good quality grooming bands instead of the cheap ones you find at Walmart. It will really cut down on breakage. It also helps to have pair of band removal scissors to cut the bands out. If you try to unwrap them, you'll break more hair.
Both these links have great bands and also carry the scissors:
http://www.dog-bows.com/cgi-bin/TheF...atB&category=0 http://www.laineeltd.com/cgi-bin/laineeltd/index2.html