Once a 32G, always a 32G, right? Not exactly. All sorts of factors can affect your bra size from year to year.

To demystify what exactly those are, Lori Kaplan, co-owner of Bra Tenders (whose clientele is 90% full-busted women, outside of their huge theater, TV, and movie business) sat down with me after my Annual Bra Checkup to give me a cheat sheet.

When to Get Fitted

Head to Your Local Expert Fitter If You…

• Lose weight
• Gain weight
• Start a new workout regime
• Are pregnant. Check in when you notice your bra is uncomfortable or not covering your breast tissue (expect changes throughout; one woman Lori fitted started at a 32A, was fitted in a 34DD at 6 months, and a 34F at 9 months)
• Are experiencing other hormonal changes, such as post-pregnancy or menopause. Evaluate every 6 months
• Go on birth control. Again, this causes hormonal changes, which may change your bra size. Check in after one month
• Notice your breast tissue is not fully covered (like on the sides near your armpits). Of course, make sure you are putting your bra on correctly first to see if that’s causing part of the problem
• Feel like you are wearing the wrong bra size

If you don’t experience any major lifestyle changes, a good rule of thumb is to head in once a year for your own Annual Bra Checkup. Why?

1. Stocking up online doesn’t always work asmanufacturers change little things in the design of their bras. Bra Tenders senior fitter Cristal advised that if I bought my favoriteFantasie Molded Balcony Bra at 3 different stores, I would likely have 3 slightly different bras, depending on when the bra was stocked. One year I might need a 32G, the next a 32FF.
2. Similar styles by the same brand could fit completely differently: I’m a 32FF in theFreya Arabella, and a 32GG in the Freya Frankie, though both have the same 3-piece cup design.
3. There is no standardized fit for different bra manufacturers.I wear a 32G in most of my Freya and Fantasie of England bras, but a 32H in the Panache Ariza. You can always use an online site like Bratabase to help you compare sizes, but the only foolproof way to get a good fit is to go to your favorite fitting expert.
4. Your body may change slightly from year to year, even if you don’t experience anything from the list above. If, for example, the elasticity of your skin changes, you might need a padded cup for extra lift. Let’s be honest:we all go up and down in jeans sizes over the years — why wouldn’t we expect changes in our bra sizes?
5. Like me, you may justneed a once-a-year refresher on getting great fitfrom your bras.

Think a yearly checkup is just too often, considering the price of big-busted bras? Tomorrow I tackle exactly when it’s time to recycle those boulder holders.

Click on the map below to get a bra fitter in your area.