While throwing a pair of jeans in the dryer sounds fast and easy, it's not so great for your denim. Dryer heat can compromise the yarn and lycra, so your pants will likely be out of shape within three years' time. If you're pressed for time, you can tumble-dry your jeans — but only on the lowest heat setting. Another exception, according to Mazur, involves vintage denim. "Vintage jeans often get a bit stretched out with wear," he explains. "Throwing them in the dryer briefly can help them regain their shape."