Experts say a lot of people are not as protected from the sun as they think because of some common mistakes.

“You must put on 1 oz of sunscreen, that’s the amount in a shot glass, to cover your whole body. Most people don’t put on that much,” Dermatologist Dr. Melissa Piliang said.

Skimping on sunscreen is one of the most common mistakes.

Dermatologists say that slip-up leaves you far more likely to get burned.

“If you’re putting it on too thin, you’re not getting an SPF 30, you’re getting more like an SPF 10, so sometimes it’s easier to put on a higher potency to get you to 30, but you want to put on a nice, thick coat,” Piliang said.

Another sunscreen slip-up is waiting to apply it until you’re already at the pool.

Putting it on 10 to 15 minutes before going outside gives it a chance to absorb into your skin.

The American Academy of Dermatology recommends choosing a sunscreen that is SPF 30 or higher, and pick one labeled ‘broad spectrum’ to protect against UV-A and UV-B rays.

Another common slip-up is skipping the reapplication.

Sunscreen should be reapplied at least every two hours, especially if you’re swimming or sweating.

Experts say be sure to pick a type of sunscreen you will actually use. Many people prefer a spray, because it’s quick and you don’t need to rub it in.

Hanging onto the same bottle of sunscreen for years is another slip-up, sunscreen is designed to remain at full strength for only three years.

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