You should visit a skin doctor even when there are no visible symptoms of any skin problem. Certain skin diseases start so passively that you cannot even feel their existence. When the condition goes worse then only you can realize the problem. A regular visit to a skin doctor would help you avoid such problems.
Moreover, a skin doctor can suggest you the best skincare regime suitable for your age, skin type and local weather. Due to global warming and other environmental changes, we sometimes observe unnatural weather types these days. A skin doctor can suggest you the right type of protection that would help avoid harsh environmental effects.
Apart from these, a dermatologist can identify whether the signs of aging have started to appear on your skin. If yes, the doctor would recommend you certain type of anti aging skincare that would help you delay the effects of aging. Facial rejuvenation, skin toning, microdermabrasion, cleansing and other facial treatments help get back younger looking skin and reduce the effects of aging.
Finally, if your skin has already undergone irreversible damages such as sun burn, a skin doctor can help you revert it back through cosmetic surgery or other invasive skin treatments. It is very important to deal with reputed dermatologists who have long history of helping people. Run a web search and find the best dermatologist in your locality.