5 things a bra fitter with 18 years of experience wishes people knew about bras and their bodies

• Business Insider spoke to Kimmay Caldwell, a bra fitter with more than 18 years of experience.
• She called bra sizing "the worst game of telephone ever."

Kimmay Caldwell is a bra fitter and educator with 18 years of experience in the underwear industry.

She has worked in family-run boutiques and for high-end brands like La Perla, and her experience comes with a treasure trove of knowledge.

Caldwell told Business Insider she has seen thousands of naked bodies in her career but estimates 99% of clients are wearing the wrong bra size.

While in the fitting room with her clients, Caldwell told BI she learned about the misconceptions people have about their bras and bodies.

"It's like the worst game of telephone ever," Caldwell said.

Here are five things she says people should know about buying a bra that's right for their body.

Bra sizes can keep changing, Caldwell says

"I do wish when I was 20, I knew that breasts change," Caldwell told BI.

She said when she was a full-time bra fitter, her most common client age group was people in their mid-50s. Caldwell attributed this surge to clients being menopausal or perimenopausal, which she said is like a second puberty and means breast sizes can drastically change.

"Our hormones completely change, and our bodies completely change, and no one's really prepared for it," Caldwell added.

She said that as the body changes, breasts change too so it's likely your bra size will need to be updated regularly throughout your life.

No two bras fit the same

Caldwell told BI that depending on the fabric, fit, brand, and material, you could be a different size in every bra style you try.

So, she said it's important to go for the bra that feels good rather than sticking to a one-size-fits-all mentality.

Bras don't have to be uncomfortable

"In most cases, if your bra fits well, it won't even feel like you're wearing a bra," Caldwell said.

She told BI that underwire bras currently provide the most popular breast shape, but their widespread popularity is more about trends than added support. She added that in the 1950s, the trend was for a pointed bust, and in the 1990s, it was a pushed-up bust.

"Breasts did not change, how we shaped them changed. So right now, we're just going through another trend," she said.

There's no such thing as a 'normal' size or shape

Where retailers are increasing their in-store clothing ranges for plus-size and disabled bodies, they are still lacking in offering the same options in lingerie departments, Caldwell said.

"There's nothing wrong with your body just because the popular stores don't have what I consider popular sizes," she told BI.

Caldwell added that breasts being uneven is common, likening them to hands and feet. She recommended The Balanced Bra Company and Livi Lu Lane, which stock bras designed for this.

Caldwell says the band is the most important part of a bra

Caldwell also described the mechanics of bra sizing, and offers an online course on how to do this yourself. She said cup size is relative to band size, meaning a D cup on a 32 band is not the same as a D cup on a 34 band.

"As the band size changes just to keep that same cup size volume, you have to change the actual letter," Caldwell told BI. That means a 32C is the same volume as a 34B and a 36A, she added.

"The band needs to be snug like a hug and stay parallel and in place in order for the rest of the bra to do its job. If the band doesn't fit, nothing else will work," Caldwell told BI.