Wearing a good-fitting sports bra can improve your enjoyment of and performance in your favorite sport.

At one point or another, most active women have experienced the uncomfortable and unattractive effects of a poorly fitting sports bra: chafing, pinching, spillage, bouncing, poking and the dreaded “uni-boob.” 1

What most women don’t know is that a great-fitting sports bra prevents all these unsavory effects and is readily available online and in sportswear retailers 1. If you love being active but hate your sports bra, then you need to know these 10 things about buying a sports bra:

1. Most of the Support Comes From the Band Around Your Rib Cage

Sports bra cups and straps get a lot of the attention, but the band that hugs your rib cage is actually the most valuable player, providing 90 percent of the support, according to Susan Nethero, founder of Intimacy lingerie stores. A sports bra’s band should offer a firm fit, without slack.

“The band should be a little bit tighter than your lingerie bra because it’s going to hold you in as you bounce around,” says Tahra Makinson-Sanders, founder of TMak Sportswear and designer of the TaDa sports bra. The band should sit flat against your skin, just underneath your breasts, and it shouldn’t ride up in the back. Makinson-Sanders also recommends choosing a bra with a hook-and-eye closure so you can adjust the band to fit more snugly or loosely depending on the intensity of your activity.

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2. You’re Wearing the Wrong Size

You’re not alone with your ill-fitting sports bras. In fact, 80 percent of women wear the wrong-size bra, according to a study conducted by Wacoal America in 2004. When it comes to sports bras, it’s common to want to err on the side of too small, as having everything smashed together makes you feel more supported.

But a too-tight fit is the root of most of the uglier experiences. A band that’s too snug can cause painful chafing, overly tight straps may dig into the shoulders leaving bruises and spillage is a sure thing if your breast tissue overflows your bra’s capacity. If you’re in the minority, wearing a sports bra that’s too loose, you’re not getting the support you need, which can lead to damage to the breast tissue, especially in high-impact sports. The solution? Get a custom fitting (see #6) 1.

3. Encapsulation Bras Beat Compression Bras

There are two main categories of sports bras: encapsulation and compression. Compression bras are old standbys that press the breasts to the body without separation, leading to the dreaded uni-boob shape. Encapsulation bras, on the other hand, provide cups for each breast, just like your everyday bra. Although compression is a classic, encapsulation provides the best support.

“The breasts move in a circular figure-eight motion,” explains sports bra designer Tahra Makinson-Sanders. “They go up and down, left to right and in and out, and a compression bra won’t be able to handle all that movement. If you’re riding a horse or you’re going for a run, you want a bra that encapsulates each breast to minimize all that movement,” she says. Even if you’re doing yoga, a compression bra is still not your best bet, because it won’t prevent spillage in a downward dog if you’re well-endowed. Go ahead and give it a try. “You can never go wrong buying an encapsulation bra, but you always go wrong if you buy a compression bra,” Makinson-Sanders says.

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4. Sports Bras Have a Short Shelf Life

Open up your lingerie drawer and you’ll probably see something you shouldn’t: sports bras you bought three years ago. With proper care, you can keep your everyday bras a lot longer than your sports bras because they don’t undergo as much wear and tear as your active bras do, and you probably have more of them.

“The lifespan of a sports bra is pretty short,” says sports bra designer Tahra Makinson-Sanders. “It goes through a lot of torture.” All that bouncing, pounding, sweating, washing and drying can cause the fabric fibers in a sports bra to degrade quickly, which means you lose crucial support where it counts. “If you’re at 12 months with a bra, it’s time to go,” she says.

5. Larger-Chested Women Don’t Have to “Double-Bag” It

If you’re a C cup or larger, getting the support you need for higher-impact sports can be a struggle. Some women even resort to wearing two sports bras — one on top of the other. If you’ve ever “double-bagged” it, you should know that you don’t have to. A high-quality encapsulated sports bra made for larger shapes and sizes that fits well can provide all the support you need. For larger sizes, sports bra designer Tahra Makinson-Sanders recommends a style with an underwire. “I worked in a sportswear store where I helped women try on bras, and if I even said ‘wire,’ they said ‘Nope, not gonna try. It’s not gonna do it.’ But the few that I could get to try it on were so pleasantly surprised,” she says. “I wholeheartedly recommend trying one. I think you’ll really notice the amount of support is fantastic.”

Read More: The Best Sports Bras for Big Breasts

6. You Can Get a Custom Fit for Your Sports Bra

Most women wouldn’t hesitate to get fitted by an expert salesperson at a department store for their regular lingerie bras, but when it comes to sports bras, it seems anything goes. That often leads to a poor fit. Depending on where you live, you likely have a local specialty women’s activewear store that can provide an individualized fitting. The activewear experts at those stores, in addition to taking precise measurements, can also make recommendations for the best bras for your body shape and sport.

7. Fabric Technology Is More Than Marketing

Have you ever considered what your sports bra is made of? You should, because it can make a big difference. “Do not buy cotton,” says sports bra designer Tahra Makinson-Sanders. “People might think that cotton is soft and wonderful, but cotton is awful for athletes. It holds water like a sponge,” she says.

Instead, she recommends looking for fabrics that are breathable and wicking, meaning they draw moisture away from the body. Many sports bra manufacturers are developing and patenting their own fabrics these days, but CoolMax is one of the originals and a good example of the type of fabric you want in a sports bra 2. Even if you’ve never heard of the fabric your sports bra is made of, check the label — it should say it’s “breathable” and “moisture-wicking.”

8. You Need More Than One Sports Bra

You have five or six lingerie bras but only one sports bra. That’s a big no-no, says sports bra designer Tahra Makinson-Sanders. Because sports bras take a beating during your workouts, they wear out more quickly and lose their effectiveness, especially if you’re wearing the same one day in and day out. “If you work out four days a week, have four sports bras and rotate them in and out so they’re only getting worn once a week,” says Tahra Makinson-Sanders. If you’re on a tight budget, get at least two quality sports bras. And to extend their lifespan avoid putting them in the dryer.

Read More: The Best Sports Bras for Every Workout

9. Take Your Measurements Regularly

One of the main reasons many women are wearing the wrong-size sports bra is that they were measured once several years ago and haven’t been measured since. But chances are you’re not the same size you were years ago. Hormonal changes, pregnancies and the changes in fat mass and body shape that come along with an active lifestyle can all lead to rather significant fluctuations in your bra size. It’s a good rule of thumb to get your measurements taken once a year — more often if you’ve gone through a pregnancy or lost or gained a lot of weight.

10. Shop Around Before Committing

Like a good man, a good bra is hard to find. Go to a high-quality retailer and really take your time. Try on several different styles and make sure you feel comfortable and supported. Know that your time and money investment will pay for itself in the increased comfort you’ll feel while being active and the potential improvement in performance. Because even though it’s a mostly mental advantage, if you look good and feel supported, you’ll work harder and better.

What Do YOU Think?

Do you have any tips on buying a sports bra? Did you know any of these facts before reading? Which ones came as a surprise to you? Are there any that are going to change the way you shop for sports bras? Share your thoughts, questions and ideas in the comments section below. We love hearing from you!