Updated June 19, 2014.

You know you need to use sunscreen, but do you ever wonder if you're using it right? How do you know how much sunscreen to use? Do you have to keep putting it on throughout the day? What if you sweat?

Difficulty: Easy

Time Required: 5 minutes at the most

Here's How:

1. Shake the bottle well before you squirt any sunscreen out. This mixes up all the particles and distributes them evenly in the container.
2. Most adults should use about 35 ml or 1 oz. of sunscreen to cover their whole body. That's the same amount that would fit into a shot glass. It's also about the same as an adult handful. Remember, most people don't apply enough sunscreen. It's OK to use more than you think you should.

1. Apply your sunscreen 30 minutes before going out in the sun. This gives the ingredients time to attach to the skin.
2. Cover all of your skin that's exposed to the sun. This includes your back, ears, behind your knees and your legs.
3. Some studies say it's a good idea to reapply your sunscreen after you've been in the sun for 30 minutes. This makes it more likely you'll get the places you might have missed.
4. Definitely reapply the same amount of sunscreen every 2 hours, even if you haven't been sweating or in the water.
5. Reapply sunscreen as soon as you get done swimming, toweling off, or sweating heavily. Yep, the whole 1 oz.

Tips:

1. Don't forget to reapply. It's just as important as the first application. Set an alarm if it helps you remember.
2. It's OK to apply more sunscreen than you should. It's better to use more than not use enough.
3. Even if you're using sunscreen, you're more likely to get a sunburn when the sun's rays are the most intense. That's between 10 a.m. to 4 p.m.
4. Insect repellents can reduce a sunscreen's SPF by up to one-third. If you are using a sunscreen and insect repellent together, use a higher SPF and reapply more often.
   

What You Need:

• A good broad-spectrum sunscreen that protects against UVA and UVB rays.
• Body parts that are about to be exposed to the sun.