Sunscreen is essential for protecting the skin from the sun's harmful UV rays. Sunscreen should be applied to the face and neck every day, even on cloudy days. The best type of sunscreen for you will depend on your skin type and activity level. For example, if you have oily skin, you might want to use an oil-free sunscreen. If you are going to be swimming or sweating, you might want to use a water-resistant sunscreen.