I have light skin, freckles, and a ton of moles. Moles that are inspected every six months. Pretty much every six months I have 1-3 of them removed, often one of is found "pre-cancerous." This happened this week actually.
So I wear sunscreen and cover my skin. My doctor tells me to, and I listen. BUT, the real reasons I wear sunscreen is that I burn if I don't. And burning hurts. And too much tanning and sun makes you look older earlier. I generally don't wear it if I'm just biking to work or mowing the lawn, but more than 30-45 minutes in the sun and the sunscreen and hat go on.