How Often Should You Actually Buy New Underwear?

As an environmentally conscious consumer [1], I pride myself on buying and owning items that are not only good for the planet, but are made to last — whether it's Tencel dresses, upcycled pants and skirts, or shoes made from recycled plastic bottles.

But if I'm being honest, this eco outlook hasn't carried over to underwear drawer, which is jam-packed with thongs, granny panties, and cheekies from all eras of life. Some pairs I wear constantly, while others are decades old. Many are either ill-fitting, frayed, or exclusively relegated to the gym.

Looking at my eclectic assortment of underwear, I began to wonder: how often should one purchase new underwear [2], anyway? And just as importantly, is it considered taboo to wear undies past a certain date? Though a recent viral TikTok recommended replacing your underwear every six to nine months [3], that seems untenable, IMHO.

To find out, we turned to the pros: Lauren Schwab and Marissa Vosper, cofounders of Negative Underwear [4]; Katie Fritts, founder of Underclub [5]; and Joanna Griffiths, founder and CEO of Knix [6]. Read on for their expert advice.

Feel the Fabric

Fritts's rule of thumb? "If you even slightly debate that a pair looks or feels worn out, you're right!" A great way to test-drive her theory is to give your older pairs a feel. If you happen to have stretched-out underwear, that's a surefire sign to replace it. You'll also want to look out for visible holes, stubborn stains, sagging, and unravelling seams.

According to Griffiths, you'll begin to see changes in fit, fabric, and colour the longer a pair is worn, which is why she adheres to a more reasonable underwear shelf life of 12 to 24 months. "The fabric will start to stretch out and lose its shape, and the colour may start to fade," she told POPSUGAR. "You might also notice some discoloration in the gusset." Disclaimer: this is normal, due to the natural PH found in sweat and discharge.

Choose Brands Wisely

Most underwear fabrics consist of a combination of nylon, elastane, polyester cotton, and modal. "The fabric fibres themselves aren't always more or less durable per se — it's the specific fabric combinations and quality and the where and how the fabric was made that matters," Vosper said. In other words, it's more important to buy from brands that prioritise design, quality manufacturing, and craftsmanship than solely focus on purchasing a specific material.

Wash After Every Wear

To put it simply: the better you care for your underwear, the longer it will last. All experts encourage wearing underwear only once and washing immediately after. Because hot temperatures and regular detergents break down fabric fibres faster, Schwab recommends handwashing over using the machine and hang-drying all your delicates to prevent damage.

If you're travelling or in a pinch, Fritts suggests putting underwear in a laundry bag, running a delicate cycle in the washer, and then air-drying on a rack. By laying underwear flat to dry, it will better retain its shape and elasticity. And if you have access to a backyard or terrace, hanging garments to dry in the sun is also great, as the UV rays help further sanitize them.

Replace Underwear Often

Like all articles of clothing, bacteria can accumulate in underwear over time. If a pair no longer fits you, it might seal in moisture that would typically be wicked away, which can lead to potential bacterial or yeast infections. An easy solution is to replace your underwear every so often (read: 12 to 24 months, if you follow Griffiths's advice).

Keep a Healthy Rotation

According to our experts, most people typically own at least 30 pairs of underwear to cover approximately two weeks worth of laundry. "I recommend people own underwear in important categories," Fritts said. "Namely, seamless and nude pairs to wear under light dresses and pants, high-waist or control-top pairs for a defined waistline, comfy and breathable pairs for sleeping at night, and, of course, your power pairs that make you feel like a badass for exciting events and dates."

To sum it all up: it's totally OK to throw out old underwear. And, as long as they're properly cared for, it's also fine to save memorable undies for a trip down memory lane. But if you're in need of a refresh, shop some of our favourite brands ahead.