By Bradley Johnson

Advertising Age

Two decades after “thirtysomething,” get ready for 50-something. Boomers will reach a milestone at the end of the next TV season: More than half of baby boomers will be age 50 or older. They will leave the 18 to 49 demographic so coveted by advertisers. And they will qualify for membership in AARP.

Bad news for marketers? Not really. Aging boomers have the means and desire to keep spending. True, annual household spending on goods and services is about 10 percent lower in 50-plus households than in homes where the head of household is under age 50, according to the Bureau of Labor Statistics’ 2003 Consumer Expenditure Survey.

But 50-plus households tend to be smaller because the kids have moved out, and that means more money to spend on fewer people. The average member of a 50-plus household spends about $19,000 a year-30 percent above what under-50 households spend on each member of the family.

Boomers will keep spending as they move into their 50s. For proof, open the garage door. The 50-plus group today makes up 39 percent of the U.S. adult population. But the group this year will account for half of auto sales, and that share will increase to 53 percent by 2010, said Art Spinella, president of consultancy for CNW Marketing Research.

“Everybody looks at the youth market … [but] it’s 50-plus that’s going to drive the auto industry and incremental sales” for the next 10 to 15 years, he said.

Older drivers have been content to maintain their old Buicks, seeing little reason to splurge on new wheels. But as life expectancy has grown, the older market has taken on new life. CNW expects the share of cars bought by 70-plus drivers to jump from 5.7 percent in 2000 to 8.6 percent in 2010. The 20-somethings market for will go in reverse, from 8.1 percent to 6.2 percent.

The aging of the car market will accelerate as boomers pass the 50 mark. From 2005 to 2010, said CNW, the share for every 10-year age group below 50 will fall-and the share for people in their 50s, 60s and 70s will grow.

Boomers grew up with their cars, and Mr. Spinella said they “still are caught up in a car-culture mentality, where a vehicle is a primary means of defining who you are.”