Look at your skin and know your history. To maximize protection, it's important to apply the right amount of sunscreen. While most labels advise applying sunscreens liberally and often, this can be confusing since lotions, creams, gels, liquids, and sprays all cover the skin differently. Recent studies indicate that most people use only about half as much sunscreen as necessary for full protection. It is best to apply a sunscreen about 30 minutes before exposure so it can be absorbed and is less likely to be washed off by perspiration.
Many dermatologists recommend daily sunscreen use to protect against insidious sun damage.
Ultraviolet rays don't feel hot, so it's easy to be lulled into a false sense of security if there is a cool breeze or overcast sky. Ultraviolet radiation can also reflect off sand and water, pass through gauzy robes and wet T-shirts, and penetrate several feet underwater. Although a few cases of skin cancer are caused by overexposure to X-rays and by chronic exposure to chemicals such as arsenic, the chief villains are the sun's ultraviolet rays. Our bodies keep score on the amount of radiation we take in, and when the numbers get too high, the body reacts. Normally, if abnormalities occur during cell division, enzymes repair the damage.