Over time the epidermis thins and by age 60 the dermis is 20% thinner than before. It is even thinner in areas that have been exposed to the sun. But even skin that has not been exposed to ultraviolet radiation has 50% fewer mast cells and reduced blood flow, not to mention diminished elastic fiber and collagen.
Pictures are worth a thousand words so here are some to show the changes.
Actinic Keratosis are benign, dry, reddish, crusty lesions that appear on sun exposed ares like the face, ears, hands, chest and arms. Sometimes a biopsy is needed to differentiate from a squamous cell carcinoma but sun protection from an early age is the best way to avoid them.
Healthy skin can be maintained by avoiding cigarettes and sun. Those are the two most damaging influences for skin and blood vessels.