How quickly the millennials have grown up.

According to Nielsen, 61% of all Detroit area parents with children under the age of 18 are millennials.  

From the time their kids are born until they reach they are 17, these young parents will spend, on average, $233,000 per child. This does not include the cost of college.

Currently, there are 993,688 children under the age of 18 living in Metro Detroit. That makes the local millennial-parenting economy worth upwards of $231 billion. These dollars are being spent, among other things, on diapers, daycare, transportation, toys, education, electronics, clothing, and health care.

For Southeast Michigan small business owners interested in competing for a substantial portion of this multi-billion dollar pool of parental cash, they must advertise to millennial moms and dads. By almost any measurement, advertising on Detroit radio is the best way to reach this audience.

If you were one of the 2,985,400 adult consumers who listened to  the radio in Southeast Michigan last week, then odds are you heard a commercial for the Law Office of D. Todd Williams. The firm specializes in criminal defense cases involving traffic violations, probation matters, expungements, and serious felonies.

Mr. Williams has been advertising on Detroit radio every single month for the past 23 years.

"Radio advertising has been critical to building my practice," he says. "I can tell the days when my commercials run because those are the days my phones ring."

Shortly after passing the bar exam in 1995, Mr. Williams opened his firm operating from the basement of his Rochester Hills townhouse.

Mr. Williams's first cases came from friends and their referrals.

"Our franchisees love advertising on Detroit radio," says Katherine Villeneuve, Director of Marketing & Franchise Support for Auto-Lab. "They understand that radio reaches the masses, and can achieve the messaging frequency to be effective."

Auto-Lab started in 1989 as a single-independent store in Sturgis, Michigan. The company has expanded to include 21 franchises across the country. Nine of the stores are located in Metro Detroit, each operated by a local, small business owner.

Auto-Lab offers consumers the same diagnostic, maintenance, repairs, and parts as a car dealership's service department but, for what Ms. Villeneuve describes as a 'fair price'.

To drive traffic into one of Auto-Lab stores in Southeast Michigan, each franchisee contributes 3% of their gross sales to a cooperative marketing fund. Ms. Villeneuve then works with the owners to create persuasive, annual advertising campaigns.

"Each of the owners has input into how the money is spent," she says. "Afterall, because they are in the stores every day, they have the best sense who their customers are."

For the last four years, the Metro Detroit Auto-Lab owners have chosen advertising on Detroit radio as the primary way to reach new customers.