You only have to get stuck in an elevator once with someone whose perfume seems to be seeping out of her every pore to know that there's an art, and science, to smelling great. Beyond the sheer volume of choices, there's the matter of where to put it and how to make it last longer. We talked to the pros to get the lowdown on all things fragrant. Their scent-sensational answers, plus some intriguing Shape reader statistics, follow.

Unlike a fine bottle of wine, fragrance does not get better with age. How long yours will stay good depends on its formula, but the general rule is about two years.

Q: Where is the best place to apply perfume?

A: If sporting a scent for your own enjoyment, apply it to your wrist (scent receptors in your nose will quickly become immune to an allover application). When you're wearing the scent for others to adore, dab it on other pulse points, such as your throat and the backs of your knees. This way, your body heat will activate the scent throughout the entire day.

44% OF SHAPE READERS CHOOSE A SCENT TO SMELL FRESH AND CLEAN

Q Perfume, cologne, essential oil, eau de parfum and eau de toilette: What's the difference?

A The distinction is a matter of concentration. Essential oil is the purest form of a fragrance, and therefore the strongest. From there, in descending order of intensity, the list reads: perfume, eau de parfum (EDP), eau de toilette (EDT) and cologne.

For an even lighter form of cologne, try a "splash," which leaves behind a hint of scent.

Q: Whenever I shop for perfume, I get overloaded after smelling just a few. Is there any way around this?

A: Some fragrance counters provide coffee beans as a sort of "palate cleanse" for the nose. The beans work by allowing scent receptors to reach a new baseline before sniffing a second time. Wait three minutes between smelling different fragrances, and nibble on a cracker (again, to distract the receptors) while waiting. Caution: Your nose hits overload after three scents, so whiff wisely.

Q CAN PERFUMES REALLY GO BAD?

A Unlike a fine bottle of wine, fragrance does not get better with age. How long yours will stay good depends on its formula, but the general rule is two years. Storing your scents in a cool, dark place (ideally in the fridge) will increase longevity. What shortens the life span of your scent: heat, humidity and sunlight--don't keep them in your medicine cabinet, your bathroom, the glove compartment of your car or on a vanity that's near direct sunlight. A scent is no longer fresh if it smells sour or winy, gives off a distinctive alcohol aroma or no longer smells like it originally did.

Q I love my friend's perfume, but it smells different on me. Why?

A Chalk it up to your unique body chemistry, which is as one of a kind as your fingerprint. Beyond biology, a number of things can affect the way a fragrance smells on you. Medications like antibiotics or older antidepressants and antipsychotics that alter the amount and odor of your perspiration will change your scent. Also, pungent foods and spices (including onions, garlic, and peppers) and even some vitamins and herbal supplements (specifically high doses of lecithin, fish oil and vitamin E) can also affect how your fragrance smells to others.

FACT the higher the concentration, the longer a fragrance will last.

Q: SHORT OF SHOWERING, WHAT CAN I DO IF I'VE PUT ON TOO MUCH PERFUME?

A: Not a lot, but whatever you do, don't try to mask the odor by piling on other scented products. This will only make matters worse. If you have time, lather previously spritzed spots with soap and water for the most effective removal. If that doesn't work, lightly mist skin with hairspray, then wipe off with a wet towel. Why it works: Hairspray contains ingredients that dissolve chemicals in fragrance, so it helps--but only to a degree. Editor's favorite trick: Dab a cotton swab with rubbing alcohol and lightly sweep over the oversaturated area.

30% OF SHAPE READERS PICK A SCENT TO ADD SEX APPEAL

Q What can I do to make my fragrance last longer?

A The higher the concentration, the longer the fragrance will last. You can also layer a fragrance by using varied formulations. A scented body gel or wash, followed by a lotion of the same scent, helps build a powerful fragrance foundation. Finish with a few spritzes of eau de toilette and a dab or two of perfume for long-lasting impact. We like Calgon Ahh ... Spa! Asia Foaming Body Wash with Ginseng, Calgon Creaming Moisturizing Oil with Sesame Seed Oil and Calgon Energizing Body Mist with Ginger ($7 each; at drugstores). Layering a moisturizing product is particularly important if you have dry skin, which doesn't retain fragrance as well as oily skin. Our favorite nonlayering options: a heavier juicy floral like Flowerbomb by Viktor & Rolf ($95 for 1.7 oz; saks.com) and Baby Phat by Kimora Lee Simmons ($39.50 for 1.7 oz; at department stores), a blend of gardenia, lily and hyacinth blended with a dash of spicy black pepper.