Our skin is at the mercy of many forces as we age: sun, harsh weather, and bad habits. But we can take steps to help our skin stay supple and fresh-looking. How your skin ages will depend on a variety of factors: your lifestyle, diet, heredity, and other personal habits. For instance, smoking can produce free radicals, once-healthy oxygen molecules that are now overactive and unstable. Free radicals damage cells, leading to, among other things, premature wrinkles.