The One Mistake You’re Making With Your Sports Bras

For a garment that’s been worn the world over for at least a century, it seems there’s an awful lot we don’t know about our most intimate accouterment, the bra. From well-quoted statistics that suggest more than 70 percent of women are wearing the wrong size, to the ongoing hunt for the perfect strapless style that won’t, ah, let you down, there seem to be many mysteries about the undergarment that we wear every day. Thankfully, there are also a host of experts out there to help us out with all of them, from professional fitters at your favorite lingerie store to experts who can recommend a brand specifically suited to your shape and cup size.

Even with all these helpful hints, there’s always something new to learn. I was surprised by a tip I was given by Heather Cvitkovic, director of apparel merchandising at Brooks Running Company—a leading active apparel brand. “Your bra should never celebrate a birthday,” Cvitkovic said. “A sports bra needs to be replaced every six to 12 months.”

We ask more of our sports bras than our regular bras—stretching them further than a normal bra (since we stretch further during exercise than our normal range of motion) and covering them in sweat, which has corrosive properties that cause the fabric and elastic to break down quicker, even with proper care and cleaning.

To maximize the life of your sports bras, Cvitkovic suggests “having three in your rotation. This will give you multiple options and extend the life of each.” Active women who hit the gym three times a week should stick to the six to 12 month rule and keep an eye out for key signs that your bra is past its prime: a stretched band or straps, faded tags, spots that cause your skin to chafe, or a less-than-fresh scent even after being laundered.

Sticking to this easy rule of thumb will ensure that your sports bra is always in tip-top shape, so you can be, too.

To buy: Brooks Running Moving Comfort Juno Bra, $60; nordstrom.com.

This article originally appeared on RealSimple.com