Skin changes as we age. Proteins called collagen and elastin keep skin firm and elastic. Over time, these start to break down, resulting in sagging and wrinkles. Your skin produces less oil and becomes thinner and more delicate, especially around the eyes.
Skin turnover slows down. That's why there's so much caution about the Sun, as your lifetime exposure can cause uneven pigmentation and age spots. However, you can slow the aging process by avoiding sun exposure, not smoking, and maintaining a good skincare routine.