Summer is coming to a screeching halt (cue sound effect), but that doesn't mean you should necessarily stow your sunscreen in the back of your medicine cabinet. If you think you only need the 'screen when you're beach- or pool- bound -- you might be the victim of one of these sunscreen mistakes. Read the following skin care tips from expert dermatologists Dr. Linda Evans and Dr. Debra Jailman to find out how not to be a repeat offender of sunscreen slip-ups:

Mistake: Not using enough sunscreen

Solution: Don’t scrimp or be stingy with the sunscreen -- be sure to cover your entire body. Evans has a simple pocket change MO for application (note: these are general amounts -- use more if you're Kobe-sized): Put at least a nickel-sized amount in the palm of your hand and apply it to your face -- not pea or pearl size, says Evans.

Mistake: Thinking you're exempt from sunscreen because you have dark or olive skin

Solution: You're not; you still need sunscreen. We live in a different environment now -- the ozone layer is not as strong as it used to be, says Evans. And while your ancestors might have gotten away with not wearing sunscreen, things have changed environmentally, so you need to make sure to wear sunscreen.

Mistake: Not wearing a high enough SPF while outdoors

Solution: The short answer is, if you are going to be beach- or poolside, wear a waterproof/sweatproof SPF 30. "No city sunscreen for sport and sweating," says Jailman. This is especially critical if you burn easily or have skin issues like hyperpigmentation or a history of skin cancer. And if you want to wear a lower SPF, just be sure to apply it more often.

Mistake: Not applying sunblock often enough

Solution: Here are Dr. Evans' rules for how often to apply SPF if you're going to be outside all day (at the beach, hiking or the like): If you're fair, apply sunblock every two hours; if you're more olive, every three or four hours; if you're darker, three times a day. And all skin tones should apply more often if you're in and out of the water.

Mistake: Neglecting to wear sunscreen in the winter while driving or working indoors

Solution: Many of the skin cancer cases that Evans has seen are on the left side of the body (hint: your arm is exposed when you drive). Her solution? "Get chauffeured!" Kidding (though wouldn't that be nice?). To be on the safe side, she suggests wearing SPF every day.

Mistake: Using a sunscreen that blocks only UVB rays

Solution: Use a sunblock that contains titanium dioxide and zinc oxide, which block UVB and UVA rays, says Evans. (Note: UVA rays can yield sun damage and/or lead to skin cancer). Try Kids Sport Sunscreen, $9.59.

Mistake: Using a sunscreen that landed in your medicine cabinet circa '99

Solution: Make sure your sunscreen is not expired, says Evans -- don't use an old or outdated one. Jailman recommends writing a date on the bottle (if it doesn't already note one) when you buy it, and then tossing it after one year has passed. She adds that if it's a chemical-based sunscreen (as opposed to a physical sunblock -- that contains zinc oxide or titanium dioxide) it can decompose, so make sure not to leave it outside in direct sunlight.

See the rest of the sunscreen mistakes you might be making.