10 Sneaky things damaging your skin (slideshow)

Driving Without Sunscreen
The glass in car windows typically does not block UVA rays, which cause skin aging (UVB rays cause skin to tan or burn.) These rays can penetrate windows and cause damage to all skin types.

Sitting in the Shade Without Sunscreen
UV rays bounce off both sand and water, even if you're in the shade.

Wearing Old Sunscreen
Most sunscreens expire after one to three years.

Your Hairstyle
People forget to apply sunscreen on their neck and ears. Parting hair can also cause skin damage on the scalp. The best solution? Wear a hat.

Thinking Clothing Blocks the Sun
A typical white T-shirt offers you about a 7 to 8 SPF. To prevent skin damage, wear sunscreen under your clothes, or invest in clothing with Ultraviolet Protective Factor (UPF) protection that can provide up to 97.5% protection from the sun.

Thinking Your Sunscreen is Waterproof
There is a big difference between waterproof and water-resistant sunscreen. Both, however, should be reapplied after swimming. According to FDA specifications, a product is water-resistant if it maintains its SPF level after 40 minutes of activity in the water. It is considered waterproof if it maintains its SPF level after 80 minutes of water activity.

Medication
Antibiotics, including tetracycline, and some antihistamines increase the skin's sensitivity to sunlight.

A Base Tan
Some people use tanning beds to get a base tan before vacationing. A study published in the Journal of the American Academy of Dermatology, however, shows that exposure to UV rays during indoor tanning damages skin-cell DNA, harms the eyes and leads to aging. It's safer to swap the base tan for a sunscreen with a high SPF.

A Cloudy Day
UVA rays penetrate clouds more readily than UVB rays, putting those that head outdoors when the sun isn't strong at risk of skin aging and damage.

Not Applying Enough, Often Enough
At least wear a shot-glass full. Apply it all over, and rub it in well. Sunscreens only stay on for about two to 3 hours; reapplication is key to preventing skin damage.