I'm always praising the Le Mystere bras available at Nordstrom. Now, a little info on how often you should have a bra fitting. My source, Maia Bray, Manager of Intimates @ Nordstrom-Indy tells us that we should have a bra fitting at least every 6 months.
Keep in mind that weight loss or weight gain can cause your size to change. Another hint- make sure you use the first set of hooks. If you have to move them, then you know it's time to get a fitting. You should have your bra sized if either of these occur. It doesn't take long and there are so many wonderful bras out there to choose from.