You can spot them in the student's union bar in fresher's week, even if they have already cut off their dreadlocks and binned the tie-dyed trousers. There is something about people who have taken a year out before going to university; they are likely to have a more cosmopolitan worldview, and will almost certainly have more confidence than many of their peers. And, of course, they will talk with evangelical zeal about their experiences, given the chance.

Lucy McRoyal is as breathlessly enthusiastic as any. She went to Belize last year with Raleigh International, taking a diving course before working on a community project building a school in a remote village. "It was amazing," she says, "certainly a change from south London. I thought the diving would be the best part of going to Belize, but the village project was even better. "

McRoyal was unemployed before taking her trip abroad, but was so enthused on her return she organised a New Deal placement with Raleigh. She now hopes to train as a diving instructor.

Just about everyone seems to agree that taking time off after school before going to university or looking for work is a good idea. University vice-chancellors, in fact, are some of the most enthusiastic: 93% told a recent survey that they believe a structured year out benefits students' personal development.

Studies have also shown that year-out adventurers are less likely to drop out of college, and act as a motivating influence on their peers. Some 22,000 students defer their application to university or college by a year, about 5% of those entering higher education.

Perhaps the people who need most convincing are parents. Even if their offspring sign up for a structured programme rather than venturing off where the wind (or their new travelling companions) takes them, problems can still arise with host organisations, finances or plain old Delhi belly. Travelling with a respected organisation should at least ensure someone is on hand to sort out the emergency airlift if things go really awry.

The problem for would-be adventurers is where to start looking, and how to choose between organisations all offering the experience of a lifetime. "I wouldn't like to say that there are cowboy organisations out there, but there has been a proliferation of providers, and there was concern that there wasn't any regulation," says Brian Tripp, chief executive of the Engineering Development Trust, which organises industrial placements in this country. There is no central register of organisations offering year out schemes, he says, "but we're talking hundreds".

As a result, 20 of the leading year-out providers have joined forces as the Year Out Group, aiming to encourage each other to better standards in organising the schemes, and provide a quality stamp for young people struggling to decide how and where to spend their year abroad.

"What we are trying to do is put students and their advisors in the position where they have a checklist of key questions to think about," says Tripp. "A structured programme should give support and ensure a quality of experience. It should also minimise risk."

With year-out schemes costing up to £4,000 (though few travellers pay for this themselves, meeting the cost through fundraising), it is also important to be certain that the organisation in question is a reputable one.

"Our advice is to take the issue seriously," Tripp says. "Look at the range of opportunities that are available and make sure the organisation meets your needs."

Liz Newbon would agree. She spent a year in Pakistan before going to university, teaching in a girls' school in a town near Islamabad. "I wanted to travel and live as part of a different community," she says.

Newbon admits, however, that she wasn't fully prepared for the Islamic state's constraints on women. "It was quite restrictive. In some ways, it wasn't as exciting as some other people's year-out. People should try to get as much information about the options as possible, and really think about what they want to do, before they make their choice."

What you need to know

• Who can take part, and how are they selected? How many participants will be on the programme? Can they choose between programmes?

• Who benefits from the activity? What will participants gain, and who else will benefit?

• What exactly will volunteers be doing? Do they live alone or in a group? Are they paid? Is there a code of conduct for participants, and what exactly is expected of them in terms of their duties?

• How much will it cost - in detail? Is there a deposit, and is it refundable? What are the payment terms? Does the organisation offer advice on fundraising?

• What are the aims and objectives of the organisation? Is it financially sound? Try to speak to past participants about their experiences.

• What safety procedures and support mechanisms are in place? Who can participants turn to if they have a problem?

• Who is responsible for making the travel, visa and insurance arrangements? What medical precautions are necessary?

• What exactly are the living arrangements, and what is included?

• Will you have any contact with the organisation on return?

• The full set of guidelines, along with a list of Year Out Group member organisations, are available on its website www.yearoutgroup.org