> you will accrue DNA damage, and it stacks up over your entire lifetime. There is no "reset" or "heal", it just adds up. Sort of. Every time your skin gets '

> you will accrue DNA damage, and it stacks up over your entire lifetime. There is no "reset" or "heal", it just adds up. Sort of. Every time your skin gets 'red' due to sun exposure... that's due to DNA damage. However, cells have several mechanisms to repair DNA - otherwise we would be in serious trouble after a single radiation burn (which is what UV light does). They might fully repair an event successfully. Or they might not - in which case the damage may be severe and the cell will either die due to its effects or detect and trigger apoptosis. If the error isn't serious, it might not be detected and be passed on to future cell generations. Those are the ones you need to worry about. Specifically for the skin, given that skin cells divide quite frequently, they might be caught mid-division, which is a more vulnerable state. As you get more exposure and more damage, the chances of defects not being properly repaired increase. So you are right that, if you keep letting your skin bake, chances are you will accumulate damage that can't be repaired(over a lifetime, that's a certainty). Cancer is not the only issue. Have you seen how the skin of people that spent a lifetime working under the sun without adequate protection look like?