Four months into retirement, Jim Guenther has no regrets.
An accountant, he carefully calculated how much money he and his younger wife -- who is still working _ would need when he called it a career in January, a couple of days after his 66th birthday.
Guenther, of New Berlin, Wis., said he felt like he was running out of energy as the head of Economics Wisconsin, an agency that helps schools and teachers instruct kids about economics and money.
He said it was possible he would become bored with retirement and want to work again.
"But I sure don't feel that way now," Guenther said. "I don't want to do anything. This is pretty cool."
Guenther is among the first wave of baby boomers -- Americans born between 1946 and 1964 -- who have reached traditional retirement age and wasted little time before saying goodbye to the working world.
It's a group that a new study by MetLife Inc. says so far has defied the popular belief that baby boomers will be working longer than planned because their retirement savings got trashed in the stock market downturn.
"Despite the conventional wisdom that boomers are ready to 'work forever' and significantly extend their formal working career, many of the oldest boomers are already well into the retirement phase," the study says.
The MetLife study is a follow-up to a 2008 report that looked at the same segment of boomers at age 62 and includes 450 of the same interview subjects from the original study.
The study says 59 percent of the first boomers to turn 65 are at least partially retired. Forty-five percent are fully retired, and 14 percent are retired but working part-time.
Of those still working, 37 percent say they will retire in the next year and, on average, plan to do so by the time they're 68. Almost 63 percent already are collecting Social Security retirement benefits.
Almost all of the retirees -- 96 percent -- said they like retirement at least somewhat, and 70 percent like it a lot.
Kelli B. Send is not surprised by the apparent eagerness of baby boomers to retire.
"I just don't see a lot of people stay beyond 65, even though they say that's going to be the trend," said Send, who as senior vice president for Pewaukee, Wis.-based Francis Investment Counsel talks regularly with individual workers about managing their 401(k) plans at companies that are clients of her firm.
She said workers insist they want to retire by 65 -- even those who wouldn't appear to have enough money saved up for it.
"I think what they're saying to themselves is, 'You know, I may not have the standard of living that I once could, but I'm going to retire anyway because I'm sick of working, and I'll just figure out a way to make it work,' " she said.
She said many people seem to believe that once they become eligible for Medicare at 65 and start getting Social Security payments, they'll "make the rest of the math work."
It's too soon to know whether that optimistic approach will be successful for the first boomer retirees, but there's reason to be skeptical.
A survey last year by the mutual fund company Vanguard found that the average 401(k) retirement plan balance for those 65 and older was about $163,000.
"There's a rule of thumb that you can pull out about 5 percent of your money a year -- some advisers will tell you 4 percent -- but in the range of 4 percent to 5 percent," Send said. "So for every $100,000 you've got put away, it buys you an income of $5,000."
Even with Social Security and a pension payment -- if there is one -- that seems likely to mean some serious lifestyle adjustments for those who haven't saved enough.
Last year, a study done for the Wall Street Journal found the median household headed by a person 60 to 62 with a 401(k) account has less than one-quarter of what is needed in that account to maintain its standard of living in retirement.
Nonetheless, Send said a recurring theme she hears during her sessions with rank-and-file employees is that many yearn for "life after work."
Among retired respondents in the MetLife study, which surveyed 1,012 people born in 1946 and had a 3 percent margin of error, the biggest reason by far given for retiring was, simply, "Reached retirement age/wanted to."