It upsets me that no one mentions the link between sun exposure and aging. The people who seem to not age are commonly those who use sunscreen or protect their face/neck from the sun. Without sun exposure, the skin naturally heals and replaces scarring. This is why people with post-acne hyperpigmentation will often need to wear sunscreen for a long time while using a topical retinoid-- to both increase the rate of skin cell turnover and to make sure the new skin is adequately healed.