For 22 years, Joe and Bobbie Driscoll have cooked warm meals every week for needy folks at the Dorothy Day Center in St. Paul. When they walked out the door after retiring Wednesday, it was unlikely the center would find anyone like them again.

Nonprofit leaders call them "the greatest generation of volunteers." Largely retirees who often worked one job for life, they've brought the same dedication to unpaid service. Now, while more than 1.5 million Minnesotans volunteer, one of the largest numbers in the nation, few are sticking with an organization more than a few years.

Their attrition is prompting many charities, arts groups and hospitals to recast their volunteer programs to make them more attractive -- and less time-consuming -- to their children and grandchildren.

The older generation will be missed.

"They're the volunteers who if you ask them to be there at 8 a.m., they show up at 7:30," said Mary Quirk, interim executive director at the Minnesota Association for Volunteer Administration. "They've very loyal. They work hard. And they do what you ask them to do. They're considered the gold standard."

Younger folks bring creativity, energy and a desire to make visible change, Quirk said. But volunteering for two years, much less two decades, is not a priority.

Minnesotans, overall, volunteer an average of 42 hours a year, according to the Corporation for National and Community Service. That's the eighth-largest total in the nation.

The Driscolls, and their friend Judy Vennewitz, were honored Wednesday for 22 years of cooking everything from turkeys to tuna casserole. In the Dorothy Day dining room, the CEO of Catholic Charities, Tim Marx, was on hand to thank them.

"We didn't expect this at all," said Joe Driscoll, wearing a long apron. He began his chef duties after a 33-year career with Northern States Power Co. "This was just something we enjoyed. And we felt we were doing something worthwhile."

Vennewitz and her friend Bobbie Driscoll -- handing out grilled cheese sandwiches in the serving line -- have cooked and laughed for years alongside friends and relatives, most from the White Bear Lake area. The group included Barbara Heil, who was lost with her husband, Gerald, in the grounding of the Italian cruise ship last month.

Volunteering hasn't really been work, but fun, they said.

"But we've also seen a lot of sad things," said Vennewitz. "Coming here really opened my eyes."

About a third of the 1,800 volunteers at the Science Museum of Minnesota are "veteran volunteers," said Heather Kamia, the director of volunteers. One woman has been doing it for 50 years.

The museum so values them that they enlisted oral-history volunteers " to catch their stories before they retired," she said.

The museum, like many nonprofits, is pondering ways to prepare for inevitable changes. While it used to run just one volunteer training program a year, it now offers at least four to get more people in the door. Said Kamia: "We're trying to become more nimble."

"Organizations are spending a lot more time training and recruiting volunteers," Quirk said. "They need to spend more time bringing people on board."

To attract younger people, St. Cloud Hospital is tailoring its volunteer programs, making them shorter and more interesting, said Janene Riedeman, volunteer services coordinator.

Neighbors Inc., a human services agency serving Dakota County, is developing "skills-based opportunities" to attract younger people who might not be thrilled to spend hours folding clothes for a nonprofit thrift shop, said David Miller, volunteer manager.

It's also increasing the number of short-term volunteer slots and adding "on call" volunteers.

"Our model for the past 40 years has been based on the Greatest Generation," said Miller, who manages about 1,100 nonpaid personnel. "Now it seems like every older volunteer that leaves us, it takes two to make up their time."

The services likely to be hardest hit by impending departures are food service, food shelves and meals preparation, Quirk said. Nearly 30 percent of Minnesotans age 65 and older volunteered in food programs, according to a 2010 survey by the Corporation for National and Community Service.

But never underestimate the drive of these veteran volunteers. Those among the "White Bear Group" that left Catholic Charities on Wednesday aren't about to kick back and watch TV. They're already exploring some smaller places they could cook meals, such as a hospice, but on a less regular schedule. "We'll always do something," Vennewitz said. "This isn't the end."

Jean Hopfensperger - 612-673-4511