It's possible to take a 10-day trip with a mere three pairs of underwear. The trick: It's not made of cotton.

Though cotton can be a comfortable fabric, the right clothing -- and materials -- on the road can result in simpler and lighter travel, which can add up to cheaper travel when not needing to check a bag.

The underwear, for instance, made by ExOfficio, is a blend of 94 percent nylon and 6 percent spandex. It's comfortable, breathable and durable and can be washed in a hotel room sink or shower. Wring it out (gently), wrap it in a towel and step on it (to remove the excess water), then hang. In a couple of hours, your underwear is dry, soft and clean.

Another favorite is merino wool. It's a miraculous material that pulls sweat away from the body while also maintaining relative warmth. Better still, merino wool doesn't retain odor, which means that after a long day, a merino wool T-shirt (which can be topped with a merino pullover) can be draped on the back of a chair and smell fine in the morning.

Merino wool base layers can be worn sans smell five to 10 times without being washed. Even merino socks can take repeat uses, though maybe not as many as a shirt.

Such fabrics traditionally have been associated with active vacations including hiking and skiing. But they are just as useful for the most mundane travel, and in recent years, manufacturers of merino clothing, such as New Zealand's Icebreaker, have introduced casual lines that include dresses and hooded sweatshirts.

"I was just in London, and I didn't wear half of the clothes I brought," said Theresa Salus, outdoor program market manager for four Midwestern REI stores. "I wore the stuff that's technical gear."

Such clothes also have become more fashionable in recent years, allowing for use in more urban settings. Salus, for instance, said she relied on one pair of black pants in London that she would take to a mountaintop for being wind- and waterproof but "can also pass as nice dress-up pants."

"You're seeing a variety of different fabrics used in different ways and different companies making all sorts of different products," she said.

It is possible to outfit yourself head to toe in merino wool and/or polyester blends. Salus agrees. "My wardrobe has a mix of both, though I tend to like a wool sock better," she said.

Such fabrics even work for business travel. Remember: No one has any idea what you're wearing under that suit.