“If you go to the beach, you should reapply sun protection every two hours,” adds Dr Phillips, and if you’re entering the water, it may get washed off, so you need to apply it again once you’re out.” The rules are the same regardless of your skin tone, says Dr Phillips. But what about when it isn’t as sunny? Suppose you’re heading to work at 8 a.m. when it’s relatively dark outside, and coming home in the evening well after the sun has set. Is sunscreen necessary then? “When the UV index is low in early mornings, you don’t need to use [sunscreen] as much,” Dr Phillips explains, especially if you’re wearing more clothes. Dr Phillips recommends focusing on exposed areas, applying a teaspoon-sized amount of SPF to your face and neck.