The former engineer who became an entrepreneur is now trying to open a deli in Dania Beach, Fla.
"I want to make good sandwiches and salads," said Mastropierro, who is waiting for the necessary permits to open his deli. "My grandfather had a deli in Italy, and he taught me a lot of things when I was a little boy."
The deli will help him supplement his Social Security check, he added.
He is not alone with wanting to earn extra money. The nest egg is cracked -- or maybe was too small to begin with -- so more seniors are marching back to work.
The number of Americans 65 and older still employed has jumped 69 percent in just a decade, according to October data from the U.S. Bureau of Labor Statistics.
Just in a year, 8 percent more Americans above 65 were working in October -- the largest percentage jump in at least a decade, the BLS reported.
Vanishing pensions, not enough savings, the gyrating stock markets, zero interest in bank accounts and Social Security checks that fail to cover all the bills. The average Social Security payment is just over $1,200 a month.
"People who retired are going back to work because they need the extra money," said Edith S. Lederberg, executive director of the Aging and Disability Resource Center of Broward County, Fla. "I think it is a growing trend because people are living longer."
Lederberg herself just turned 83 last month and is still working full-time -- despite a recent hospital stay. Like many other women of her generation, she said she stayed home to raise a family and now relishes working.
"I don't plan to leave as long as I am a positive force in the agency," Lederberg declared.
Around the nation, more seniors are holding down jobs when even a decade ago they would have been at home or traveling. They range from doctors to Wal-Mart greeters.
An elder workforce has become a signature of some businesses. Grocery chain Publix, which won a national award for its hiring of seniors, benefits from mature workers who "bring experience, a strong work ethic and a positive, friendly attitude to Publix," said spokeswoman Kimberly Reynolds.
Others have used their later years to concentrate on civic and volunteer work.
Jack Brady, a retired schoolteacher, was first elected to the North Lauderdale, Fla., City Commission in 1988 while he was still working. Now 70 and a popular re-elected mayor, Brady said he likes concentrating on his city full-time.
He said he runs his city to help others -- from saving taxpayers' money to organizing a group of volunteers to clean a yard of an elderly person who can't.
"God helps us, giving the strength to do things for other people," he said.
Still, Jack Weglinski of Boca Raton, Fla., who at one time had his own business, said health may force people to cut short their working years and he's glad he saved to retire early.
"I took early Social Security at age 62 and am now 67," he said, "so, even if I die today, at least I got something."
Many younger workers are paying attention to the new reality and think Social Security benefits will be reduced -- or even eliminated -- by the time they reach retirement age.
That's why Brian Javeline, 47, of Coral Springs, Fla., is regularly working out at a gym. He wants to stay fit to work well into old age.
"You have to be a realist," said Javeline, who started a contractors' website, MyOnlineToolbox.com.
Indeed, he said he doesn't expect to ever quit working
"The word retirement should be retired," he quipped.
- The Buzz: Office space 11/14/12
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