Ground Rules

If your adult child works, set limits for what you are willing to pay for around the house (HBO? Yes. Their cell phone? No.), and agree on a specific date to start paying rent and an amount. A useful rule of thumb for how much to charge is 10 to 20 percent of take-home pay, which is less than the 30 percent the average person spends on rent, but enough to be meaningful to both parents and kids. Don’t feel right taking your child’s money? Use rent payments as a carrot by promising to hand the money back at the scheduled move-out time.

Sarah Kini, 24, recently moved from an apartment she shared in Boston’s South End to her parents’ house in Cambridge because her job just didn’t pay enough. At her mother Joanne’s request, Sarah is depositing the $800 she previously paid in rent into her savings account to be used toward an MBA; Joanne says she’ll check Sarah’s bank statements to make sure she’s depositing faithfully. She also plans to remove her daughter’s iPhone from her group phone plan and ask her to pay for gas on the borrowed car.

If your adult child doesn’t work, consider offering a work-for-rent arrangement that means something to you financially, such as mowing the lawn, paving the driveway, or painting the house. When James Peel, 24, moved home to Dallas after college in 2008, he helped his father, Bill, fix the family’s deck, an estimated $700 job if they’d hired a carpenter.