Make sure to wash your swimsuit after each and every wear—even if you don’t go in the water. “Sunscreens contain ingredients that can be damaging to the fabric and can lead to the eventual breakdown of the material,” says Marysia Reeves, designer of Marysia Swim (marysiaswim.com). To top it off, some SPFs are more detrimental than others, warns Lindsey J. Boyd, co-founder of the all-natural detergent line, The Laundress. Mineral-based lotions and oil formulations can cause yellowing or gradual stains over time if swimsuits are not washed properly. Another reason to be meticulous about washing your suit, particularly if you’re taking a dip in the pool? Chlorine is harsher on swimwear fabrics than fresh and salt water and can leave bright colors especially susceptible to fading.

But don’t throw your swimsuit in the washing machine or use just any old detergent. For best results, wash your swimsuit by hand and use a detergent specifically designed for delicates or high spandex-content fabrics, like The Laundress Sport Detergent ($14, containerstore.com), which protects the fabric’s colors and safely eliminates oils and chemicals without damaging the fine fibers. In a pinch, Boyd also swears by white vinegar for its deodorizing and antibacterial properties in lieu of detergent. If you’re away from home and don’t have detergent or vinegar readily available, Reeves suggests rinsing the swimsuit in fresh water at the very least. As for men’s swim trunks, they are durable enough to be machine washed because they contain less spandex.

How you hand wash your swimsuit makes a big difference, too. Start by filling your sink with cold water and add one capful of mild detergent or white vinegar. Let the swimsuit soak in the solution for up to 30 minutes, and then rinse with cool water. To dry, gently roll your suit in a clean dry towel, lightly pressing to remove the excess water. While it may be tempting, you should never wring out your swimsuit, as doing so may damage the spandex fibers. When you’re finished, lay the suit flat to dry.

To keep your swimsuit in tip-top shape, also be mindful to avoid these don’ts:

• Don’t soak a swimsuit overnight. This can loosen fibers.
• Don’t let a swimsuit dry directly in the sun. This may cause fading.
• Don’t put a swimsuit in the dryer. The heat weakens the elasticity of the spandex. This is the same reason why you shouldn’t wear your favorite bikini in a Jacuzzi.
• Don’t hang a swimsuit on a metal rod to dry. Hanging can alter the shape of the garment, while the metal rod could leave a rust mark that’s impossible to get out.
• Don’t sit on rough surfaces while wearing a swimsuit. The concrete beside the pool or wood from the lounge chairs may snag the swimsuit material. Always lay down a towel before you sit.