Gym clothes made with high-performance fabrics require special treatment. Never let damp workout wear sit in your gym bag. Hang it to dry or, better yet, throw it in the washer pronto. Wash with cold water (always follow care tag instructions) with unscented detergent. Extra chemicals, like perfume or fabric softeners, can clog the high-tech fibers and reduce wicking and antimicrobial performance. When your workout wear stops smell-fighting or sun-blocking, time to replace. More details here.