While some seniors stick with their careers, others must reinvent themselves to remain in the workforce.

"Some folks have tried to stay in the same field they were in in the past, and they can't get a job," said Lita Levine Kleger, director of partnership development and outreach at Experience Works, a company that aids seniors in their job searches. "Some folks, their industries have gone away -- what they did for many years is no longer what they can do, just by necessity."

Kleger added that many need to move to care for an elderly parent, and then are forced to find a job in a new area with different industries.

One of the biggest shifts is from manual labor to desk jobs as seniors find themselves less physically capable. This often requires new computer and organizational skills to compete with younger job seekers. More technology can mean more opportunity, however, especially for older workers looking to stay close to home.

"People can now work in all different arrangements from many locations because of technology," said employment expert John Challenger. "That's changed the way employers contract with people."

Learning new skills and finding different working arrangements can even allow seniors to remain with their employer for years.

"We're seeing more people and companies say, 'Why would you want to discard that experience and know-how that you've built?' " Challenger said. "Maybe they don't want to work 40 or 50 hours a week, but they have specific knowledge of the company. That makes them more valuable than someone who's coming for the first time." - Matt Connolly