(MONEY Magazine) – Faced with a high school senior who'd like to take a year off before college to go find himself, most parents would either roll their eyes, put their foot down or grab their heart with a shortness of breath. What they should do, however, is raise a glass. Encouraging an exploratory year off--rather than sending your child off to college a scant three months after high school--may be the best way to guarantee that he'll enter his freshman year with a clear sense of what he wants to do with his life, the ability to manage money and a better shot at graduating in four years (something just 37% of incoming freshmen do, according to the Education Trust, a nonprofit group in Washington, D.C.).

It's called a gap year. Depending on how the student spends the time, it can be an expensive choice--but it doesn't have to be, and it may actually improve your child's employability later. Some students volunteer, others travel with organized programs (many of which charge fees on par with college tuition) or on their own, learn a language or check out a career by doing an internship. Some earn money for school. (Slacking off doesn't qualify.) Most schools recommend that gap candidates apply to college while still in high school, rather than waiting until after their year off. Only once they've been admitted should they ask for a deferral.

"Gapping" has been popular in Europe for years--even Princes William and Harry did it. But although it's been percolating in the U.S. for decades, the concept is just now becoming popular, says Holly Bull of the Center for Interim Programs, which helps students find worthwhile ways to spend the time. Two decades ago, she had 80 clients. This year she worked with 200 and is looking to open a third office.

Topflight schools including Harvard, Yale and Sarah Lawrence have endorsed the concept. Harvard admissions dean William Fitzsimmons has co-written a paper called Time Out or Burn Out for the Next Generation (you can find it at harvard.edu) arguing that after the pressure students face in high school, devoting a year to their own pursuits prepares them for academia.

"Students come back with a clearer sense of purpose about what they want to study and do for a career," says Paul Marthers, dean of admission at Reed College, where 10% of students defer. The year also helps them grow up socially. Some gappers spend time in countries where there's no minimum drinking age but where binge drinking is frowned upon. Others get partying out of their system. Almost all gain a sense of financial, social and intellectual maturity.

So if a gap year is such a swell idea, why aren't more kids doing it? To be frank, probably because of you.

Moi, you say? Yep. Many parents shudder at the thought of their children straying from the well-beaten path. Some worry that their kids will lag behind in the job hunt or, worse, fall so in love with life outside the classroom (or perhaps with some gorgeous Costa Rican) that they'll never matriculate.

But after the initial hand-wringing, many see the benefits. Connie Kurz, for example, was skeptical when her daughter wanted to spend a year in Austria learning German and becoming a certified ski instructor. A year later, Kurz was among the converted. "Caroline learned to live independently. She could negotiate cities. She held her own with kids in their twenties," Kurz says. "Basically, she grew up."

There are questions, of course, about how much financial aid gappers receive, what exactly your child wants to do and, of course, who pays for it. So ask away.

• How much does it cost? Some volunteer programs, such as AmeriCorps, actually pay your son or daughter. Others, like adventure trips, cost thousands of dollars. (Some of them are not-for-profit, so at least fees are tax deductible.) Before your child begins to search for a program that's right, agree on a budget. If he wants to make his own plan, work together on a cost-conscious itinerary. Adam Haigler, an Evergreen State freshman who recently volunteered in Costa Rica and in New Zealand, was able to save $1,000 on air fare by using an international student ID card (available at myisic.com).

• Shouldn't my kid pay for this? Some of it. "In England, the student is expected to get involved in the financial aspect of paying for a gap year," says Rae Nelson, co-author of The Gap-Year Advantage (and Haigler's stepmother). Assuming your child will work to save up for gap-year expenses, encourage him or her by matching the savings.

• Is financial aid affected? When a student defers, you have to reapply for aid for the following year. If your child spends a year working, however, he might earn enough to contribute more, says Harvard's Fitzsimmons. Additionally, the gap year will have given you extra time to save. Earning and saving sound great on the surface, of course, but it's possible that they could reduce the aid package that will be offered. It won't be by much--your savings can't change too much in a year--so it's probably worth it. But ask the school's financial aid office.

• Does a gap year look bad on a résumé? Many employers have come to look at a year off as an advantage, not a drawback. "Generally when kids are coming out of school, they don't have much on their résumés," says employment guru John Challenger. "Employers struggle to understand, is this person engaged, involved, accomplished? A gap year can be beneficial because it gives recent grads something to talk about."

• Any social drawbacks for the student? To find out, we asked one: "It's hard at times to be a year behind my high school friends," says Caroline Kurz, now a sophomore at Connecticut College. "But taking that year was one of the best things I've ever done. I felt like I gained perspective about what's important and what's not. It allowed me to concentrate on actually learning--not so much on getting ahead."