It depends on the material, but for most swimsuits, you should hand-wash if you want to maximize the lifespan of your suit. "Personally, I usually just hop in the shower with it on and then let it hang-dry," Copelman says. "Unless there is a stain on it, I rarely run it through the washing machine. Swimsuits go through the most intense environments, especially in comparison to other apparel pieces, and so when it comes to washing, the gentler, the better."