Living year round on a boat or in a motor home clearly isn't for everyone. "You need to be flexible and have a sense of adventure," says Maryellen Mencimer, 52, whose been traveling full time in an RV with her husband Gary, 50, for two and a half years, since they sold their specialty coffee business.

"You also need to make sure you have a good relationship with your spouse. It does test the relationship," Mencimer says.

Before taking the plunge, veteran vagabonds suggest that you gradually work up to full-time status. Start off with trips of a week or so, then a month, then longer. "It's a real big step to leave your community and your home," says Linda Ridihalgh, editor of Living Aboard magazine. "Live aboards are a very adventurous group." She explains that people who take to the water also have to be independent, meaning they're willing and able to fix problems and to make do regardless of the circumstances.

Yet they are also a gregarious lot and make friends quickly with kindred spirits. They rely on one another.

"I had the greatest neighbors for a long period of time," says Jan Zeller, a nurse and health-care consultant who has lived on a 45-foot sailboat for 14 years, mostly in Annapolis, Md. Zeller routinely sails to Boston, Newport, R.I., and elsewhere for meetings of the Corinthians, a group of sailors from around the world who socialize, sail together and share information.

RVers are no different, says Dick Stewart, 66, who with his wife Carol, 57, has been traveling full time in their $300,000 motor home for five years. "You meet a grand bunch of people" at campgrounds and on the road, Stewart says.

RVers have plenty of clubs. One of the largest is The Good Sam Club, with more than one million members. It sponsors "Samborees," and also helps members by providing roadside assistance, mail forwarding and other services. There are also clubs based on the make of RVs. For example, the Wally Byam Club is for owners of Airstream RVs. You'll need those friends in a pinch. Ask Jay Knoll, who quit the fast track as an executive compensation analyst at Towers Perrin in Philadelphia, and who now follows the wind. He was sailing near a small island in the Bahamas a few years ago when his wife suffered a kidney stone attack.

He radioed some people he'd met a few days earlier who were on a larger island 40 miles away. The acquaintances arranged for a speedboat to be sent and had a doctor waiting when it returned. Ultimately, his wife passed the stone and was fine.

Moral: It helps to know how to make friends.