NEW YORK (CNN/Money) - Your child just graduated from college. You're proud, you're glowing...you're racing to clear out the spare bedroom. Baby may be all grown up but he's moving back home.

Secretly, you're delighted...or distressed. Either way, you're not alone.

An online survey taken this month by MonsterTrak.com, an online job site for students, recent grads and alumni at 1,350 colleges and universities across the country, found that 61 percent of college students intend to move home for some period following graduation. Twenty-two percent said they expected to stay for more than a year.

But it's not just recent college grads cozying up to their folks. According to estimates by American Demographics magazine, 12 million adults between the ages of 20 and 34 live with their parents -- in other words, 38 percent of young singles.

And they're not all unemployed either. The reasons kids go back to Mom and Dad can vary widely -- from joblessness, divorce or debt to an attachment to the comforts of a ready-made home and a fat savings account.

Parents may like the company and help of an adult child or take satisfaction in knowing they're helping their kids get established financially. But that warm-'n-fuzzy feeling can quickly turn to resentment or foster an unhealthy dependence unless both parties agree to some ground rules from the get-go.

Experts say there are two keys to establishing a successful post-grad life with your kids: an estimated time of departure and the financial equivalent of the wooden pew. "The name of the game is not to make it too cushy for them," said certified financial planner Jill Gianola.

MAKING IT WORK       • Set a deadline for departure • Establish rules • Share chores and expenses

Your adult child needs to understand that moving home again is a short-term solution and one in which they have adult responsibilities, said Jane Adams, author of "I'm Still Your Mother: How to Get Along With Your Grown-Up Children for the Rest of Your Life."

Behind most reasons for moving home is a goal your children wish to achieve -- get a job, save for a down payment or pay off student loans. And implicit in that goal is a time frame -- three months, six months, a year or more. What's important is that both parents and child agree to a time frame and discuss realistic steps the child can take during that period to achieve his or her goal.

Both parties also should spell out what the child's contribution to the household will be. That may include helping with the shopping, cooking, laundry or lawn care, and, if your child is employed, contributing to household expenses. You also should make clear what cash contributions will cover -- for instance, room, food and utilities but not car insurance.

Many parents are reluctant to charge their kids market rent. And that's fine, experts say. But you can help speed your kids journey to financial independence by doing one of two things or both:

Calculate the difference between what they would pay to rent a real apartment and what you charge them, and insist they put that difference away in a savings account or Roth IRA. "You want to get the child used to a certain cash outlay," Gianola said. And the added bonus is, they're saving money at the same time.

Or, if you can afford to, you might save the money your child pays you in rent, then give it back when he or she moves out. You don't need to tell your child you're doing this, however, in case you change your mind in the meantime.

As a parent, there is at least one potential financial advantage if you have an adult child living at home. If you pay more than half of the household expenses, you can claim "head of household" status on your tax return, assuming your adult child is single and regardless of the child's age or how much he or she makes, said David Mellem of the National Association of Tax Practitioners. As head of household you're entitled to a higher standard deduction and more of your income will be taxed at the lowest tax rates.

There are plenty of other potential benefits, too. Many parents, for instance, relish the prospect of re-filling their empty nest, especially those who might be living alone after being divorced or widowed. And the notion of living with family as a single adult is not unheard of -- it's common in many cultures and can be satisfying to family members so long as it's understood the returning child is an adult, with all the privileges and responsibilities that entails.

But, of course, there's nothing like living with your mother to make you regress to the days of sloth and dependency. That's why experts recommend parent and child establish what each expects to get out of the arrangement. Setting rules is like drawing up a lease -- both parties understand and agree to the terms of the deal, Adams explained.

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Doing so is useful should your adult children fail to fulfill their end of the bargain. For instance, say your daughter moves home because she doesn't have a job and then doesn't make a concerted effort to find one. You might insist she get an apartment with a roommate and offer to pay her portion of the rent for a few months but nothing else, Adams suggested. "If that means she has to get a McJob to make ends meet, so be it because that's the way the world works," she said.

Or say your adult children have a job but are living at home in order to pay off debt or save enough to live on their own. If you see them instead "wearing -- or driving -- their paycheck" and not making a real effort to save, don't hesitate to insist they change their habits or start looking for a new place, Adams said.

At all times, she added, both of you should be clear about one thing: "The option of moving back is the parent's choice."