Many of us prepare for time in the sun by grabbing a swimsuit, a towel, and a tube of sunscreen from the assortment on the bathroom shelf. But such an offhand approach to sun exposure can lead to progression of a sunburn, such as sun-damaged skin with serious long-term consequences that include premature aging of the skin and increased risk of cancer.

Protecting your skin can be as simple as good sunscreen, great cover-ups, and knowing when to take a time-out. So where does the confusion come from? First, you need the right sunscreen. Sun protection is based on blocking out as much of the sun's intense ultraviolet light as possible. Sunburn is caused by ultraviolet B (UVB) rays, which mainly affect the topmost levels of skin. The sun protection factor (SPF) you see listed on sunscreen bottles is a measure of protection against these UVB rays. But ultraviolet A (UVA) rays penetrate deeper, altering cell structure, darkening skin, and weakening its immune system.

Sunscreens commonly promote the SPF factor. The higher the number, the greater the protection against burning UVB rays. And the high for UVB protection has just been raised to 50+, which is good news. But it's also important to get protection from damaging UVA rays. Now sunscreens will also carry a one- to four-star rating system for UVA protection.

But sunscreen is only as good as its last application. Studies have shown that people apply sunscreen with a dangerously sparing touch. The rule of thumb is an ounce for the average adult. Work it in well before going out into the sun and reapply every couple of hours — or more often if you get wet or sweat.

I tell my clients sunscreen is not like plaster. It won't just stay on your skin.

It won't last forever in storage either — sunscreen can expire. Many sunscreens have a chemical base. Those chemicals break down over time. So you may want to reconsider the bottle that's been rolling around in your trunk for a few years.

Even used properly, repeatedly and in a timely fashion, sunscreen isn't an all-day pass to Sun City, and it can't protect against all of the sun's harmful rays.

For the most complete sun protection, put on more clothes — and not just any clothes. If your cover-up is an over washed T-shirt or a wisp of gauze, don't assume it will protect you; a cotton shirt rates only SPF4. Instead, invest in some sun-protective clothing — look for the ultraviolet protection factor (UPF) rating — and a UPF laundry rinse to boost protection for other clothes. A broad-brimmed hat will trump a baseball hat or golf visor, and UVA/UVB-rated sunglasses will protect your eyes.

Finally, take a time-out. Because ultraviolet rays are strongest from 10 a.m. to 4 p.m., even on overcast days, schedule outdoor activities for other times of the day. Seek shade. And if you can't avoid the sun, try to limit the amount of time you're outdoors during peak hours.

Protect your skin, and your health, by playing it safe in the sun.