Crow’s feet, brown spots, and wrinkles are all classic signs of sun damage, yet most people think they are part of the unavoidable cost of getting older. It is not hard to see why. In the United States, there is a definitive tanning culture. Now, “DNA repair” and “miracle” products line the shelves, promising much more than any cosmetic could possibly achieve. And, still, people commonly buy them for $90 an ounce.