Work experience," explains Dennis Richards, head of St Aidan's CofE High School in Harrogate, "helps pupils learn to tread the fine line between taking the initiative and doing what they are told."
A big supporter of young people having the chance to sample the workplace, he says it is vital to give pupils a "reality check" about working life.
Learning to get on with other people, he says, is also core to the exercise, as you can't always choose your co-workers.
Most headteachers agree that work experience can be a crucial eye-opener for pupils more used to following exam syllabuses, having every hour timetabled and being told what to do.
But what if "taking the initiative" on a work placement boils down to putting sugar in a colleague's tea without asking first? Or kicking the photocopier when it won't print on both sides of the paper? Is it still of value?
Every year, many Year 10s and 11s will find inspiration for their future lives during their two weeks in the workplace.
But there will also be a great many who drag themselves to placements where they will do little more than they do in their Saturday jobs, but unpaid.
Some will follow a structured scheme of activities with dedicated mentors while others will be largely ignored.
A recent survey of employers by bosses' organisation the CBI confirms this mixed picture with the alarming statistic that only 37 per cent of companies were satisfied with the work experience they offered.
A separate report for the CBI, conducted in 2007, found that "many" young people on work experience did not receive a briefing on the company, did not have explicit goals and did not receive feedback.
More generally, a new KPMG investigation on schoolemployer partnerships for the Education and Employers Taskforce charity, found that relationships between schools and businesses were highly valued by schools, but arrangements were often "ad hoc" and "inconsistent".
A small proportion of schools, 18 per cent of primaries and 4 per cent of secondaries, even claimed their relationships with companies were of "little benefit".
Ben Slade, headteacher of Manor Community College in Cambridge, says it is up to the school to make sure placements are more than an exercise in kettle management.
"Work experience is only as good as the person organising it," he said. "If you have someone organising it who thinks it's a pain in the arse, you will get the pupil bagging bananas in Kwik Save, which will only teach them 'I don't want to do that'."
But Peter Kent, head of Lawrence Sheriff School, a boys' grammar in Rugby, Warwickshire, disagrees that the more "boring" placements fail to teach pupils anything. Boredom, he says, even for headmasters, is part of life.
"Some go to shops. Others go to exciting placements, but that's life; not everything you do in work is incredibly exciting or dynamic," he says.
Despite this optimism about the more mundane jobs, Mr Kent employs a part-time director of careers, work experience and enterprise, Laura Kisby, to ensure each boy has a tailor-made experience.
Pupils have worked at Aston Martin and Pinewood Studios. One mother spent a week in a youth hostel in London accompanying her son on a placement at London's Natural History Museum.
But Ms Kisby says there is a "phenomenal" amount of paperwork involved in arranging placements, even with the help of the local Education Business Partnership and Connexions, which "quality controls" placements for essentials such as insurance.
"You need someone who can devote their time to this sort of thing," she says. "A teacher might only get four to six hours a week to do it, which would be difficult from an admin point of view."
But she agrees that seemingly basic jobs in mundane organisations should not be sniffed at. "We do have some going into shops," she say. "There can be an attitude that they are going to stack shelves, but we have found they are getting a view of all areas of the company, from HR to accounts."
And anyway, she adds, a potentially unfulfilling placement can be rendered worthwhile by making pupils fill in work experience diaries and find out key facts about the firm. "This forces them to talk to people and learn how companies work."
Many companies are trying hard to go beyond offering a seat at a computer. In recessionary times, there are more free seats, but with fewer staff to guide young people, there is more chance of them doing little more than surfing the net all day.
Some heads find the idea of school as merely preparation for work as distasteful. However, the CBI says companies should make the most of their opportunity to shape future employees.
Simon Nathan, policy adviser for the CBI, says: "You've got two weeks with a young person. You have to ask 'have you organised it well, will they do meaningful work, is it structured well?'"
He adds that one of the main complaints from employers is that they want greater flexibility in how they offer work experience. "In terms of offering something meaningful for the person to do, employers do not always want a strict two-week block," he says. "In an office, it's hard to jump in for two weeks then dive out again."
Meanwhile, many organisations are working to improve relationships between schools and employers. Local education business partnerships, while dealing with work experience, also set up careers days for primary pupils to meet professionals and learn about their jobs.
Visit Our Schools and Colleges Week was launched this summer by the Education and Employers taskforce, to encourage companies to forge better relationships with schools.
It is all vital work, those involved in the sector say, as experience in the workplace is an important rite of passage.
Ms Kisby sums it up, describing the Lawrence Sherriff pupils' return from a week at work: "They're more reliable, trustworthy and grown-up," she says. "No matter where they have been, it's as if they've grown a couple of inches taller."
Meaningful employment, every Friday
On a Friday, the corridors at Chafford Hundred Campus Business and Enterprise College seem quieter than usual: because the Year 10s have all gone off to work.
While pupils at most schools only get two weeks of work experience, pupils here go on an internship every Friday, and move to a different employer each term.
The school says the scheme has dramatically improved pupils' "employability skills", as well as raising motivation and aspiration.
Chafford Hundred Campus has run the programme for five years, thanks to its strong partnerships with local industry and commerce.
"It means the businesses can plan," says principal Chris Tomlinson. "Every week they know a pupil is going to come in on a Friday, and they can make sure there's some really worthwhile work for them to do."
The school in Thurrock, Essex, has designed its own key stage 3 curriculum, which focuses on young people's competences and skills.
In Year 9, pupils receive ample careers information, advice and guidance, which helps them decide on the following year's internship placement, as well as their key stage 4 options.
Placements are matched as closely as possible to pupils' chosen curriculum subjects. And at the end of their placement, employers give them feedback and references.
Teachers also benefit from the school's links with local industry. They can take up training placements with businesses, while employers also provide trips, workshops and presentations for pupils.
"It gives pupils a tremendously worthwhile experience," says Mr Tomlinson. "In the old two-week block, by Wednesday you were almost running out of things to do.
"But if you're doing it once a week, and it's related to the subjects you're doing at school, and you can see the relevance of it, it's a fantastic learning experience."