Shopping for the perfect bra or undergarment can be a lot like shopping for the perfect pair of jeans: They both require a lot of time, energy, and patience. If you’re anything like us, you find yourself pacing up and down the aisles in search of the right picks for what feels like an eternity, and the struggle doesn’t stop when you finally get to the fitting room. Why? Because not all garments are created equally, despite what the number on the size tag is telling you. Different fabrics and cuts can greatly alter the way something fits. So we went straight to the source (AKA bra experts) to get their advice — and make your next shopping experience a little smoother. Step one: Don’t fall for these common myths!

Myth: You only have one bra size

1. “It’s a myth that your bra size never changes! On average, it actually changes six times throughout your life,” says Ra’el Cohen, head of design for ThirdLove. Aside from the obvious reasons this might occur (hormones, weight fluctuation, pregnancy), your bandwidth and cup size could also vary due to a discrepancy between designers or US versus European labels. Therefore, know your sister sizes so you can go up or down if need be. For example, if you’re a 34C, you could also size down to a 32D or up to a 36B. Brit + Co Pick: ThirdLove 24/7 Lace T-Shirt Bra ($72)

Myth: shapewear is only for plus-size women

2. You can find the thinnest of women wearing some version of Spanx — it’s definitely not just for curvy girls. (Hello, look at the celebrities on the red carpet!) According to Item m6‘s brand director, Sanaz McCartney, their top-selling size in the shape category is actually a small. The body-hugging pieces work to hide any extra lumps and bumps or simply smooth things out. The options are endless and there’s a style for every shape. Brit + Co Pick: Item m6 Shaping Thong Bodysuit ($84)

Myth: a white bra goes undetected under your clothes

3. “The best way to keep your bra hidden is to find a color that matches or complements your skin tone,” says Cohen. A stark white bra will show through under both light and dark tops. Brands like ThirdLove have done a good job creating undergarments in a diverse range of colors to help solve this problem. Brit + Co Pick: ThirdLove 24/7 Classic T-Shirt Naked Bra ($68)

Myth: go a size smaller in shapewear

4. This idea is all kinds of wrong. Stick to your normal size when reaching for essential shapewear items. McCartney says you want to “define and support the silhouette, not constrict,” so look for breathable products that will slim and smooth — it’s that simple. Brit + Co Pick: Simply Perfect by Warner’s High Waist Thigh Slimmer ($20)

Myth: If you find a bra that works, wear it for life

5. All bras wear out over time, no matter how high-end the designer or cost. After a while garments will stretch, which means they’ll no longer be doing their job of lifting and supporting. Treat yourself to a new bra on the regular, ladies! Brit + Co Pick: Natori Feathers Underwire Contour Bra ($68)

Myth: Shapewear causes health issues

6. Thanks to innovations in fabric and design, gone are the days of suffocating undergarments and constricting silos. Nowadays, pieces are built to move with you, not against you — they’re stretchy and meant to be worn daily if need be. Brands even have built-in compression, which stimulates blood circulation to give you an extra energy boost. Brit + Co Pick: Spanx Spotlight on Lace Bodysuit ($74)

Myth: toss your bra in the washing machine

7. Washing machines (especially dryers) can wreak havoc on a bra, so stick to hand-washing when it comes to weekly cleaning. Opt for a gentle detergent or lingerie wash and hang dry. It’s a little extra effort, but it’s worth it since you’ll end up with longer-lasting garments. Brit + Co Pick: The Laundress Delicate Wash Detergent ($19)

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