Goodbye empty nest: Millennials are moving back home

If your adult child moved back home after graduation, your family is part of a growing trend in America. Research shows that for the first time in more than 130 years, young adults are more likely to live with their parents than with a spouse or partner in their own home. So what's behind this societal shift? Some experts point to changing attitudes toward relationships and marriage among millennials, but economic factors also play an important role. As employment and wages have dropped and college loan debt has risen, moving back in with mom and dad is a cost-effective housing option for many adults ages 18 to 34.

If you have a millennial living under your roof, one of the first things you should talk about as a family is money. "Everyone needs to be on the same financial page," says Leslie H. Tayne, a debt-related attorney based in Melville, N.Y., and author of Life & Debt. All expenses—from food and bills to transportation and rent—need be discussed and outlined.

Not only will discussions about expenses and expectations prevent conflicts down the road, they can help your adult child to learn to save money, pay down debt, and reach financial independence.

Tayne says that parents should make it clear that if an adult child is living at home, they must be working. It might not be their dream job, and it might not even be full-time, but they need to have a paycheck coming in so that they can begin to learn about budgeting.

"In order to appreciate and understand money, you should try to take on your own bills sooner rather than later," says Tayne, who suggests having your adult child put together a list of all of their financial obligations (rent, car payment, cell phone bill, student loans), the date each payment is due, and how much each requires. Even if you are contributing to some payments, "your child should know how much is being paid and when."

If there is room in their budget to start saving money for retirement, encourage them to start a Roth IRA. Financial experts know that retirement accounts started when you're in your teens or 20s can end up being worth much more than those started later in life. Finally, Tayne recommends checking in with your adult child every six months or so about the living arrangement. That way you can gently start nudging them toward independence—both financially and residentially.