Retirement used to be about hard-earned relaxation—lounging on a beach, with golf games and cribbage tournaments as the only appointments on the calendar.

But if a September AARP survey of nearly 5,000 workers ages 50 to 64 is any indication, work may be the new golf. More than one-third of those surveyed expect to work at least part time during retirement, with almost half of those respondents wanting to switch careers for their second act.

If you are hoping to work in retirement, whether in the more common part-time capacity or in a new full-time job, consider preparing for this life shift before you are actually retired.

Decide whether you want or need to work in retirement

According to the Government Accountability Office, the average American doesn’t have enough savings to retire in the traditional sense—that is, at age 62 and without ever having to find ways to earn income again.

It’s a generational shift related to increased longevity, says Ric Edelman, an independent financial advisor and CEO of Edelman Financial Services LLC in Glenview, Ill. When Social Security was designed and people started retiring at 62, they weren’t expected to live much longer. Now, life expectancy exceeds that retirement age by 20 or 30 years, meaning people have to be able to support themselves for a lot longer.

“People across the country have not sufficiently prepared for retirement—many because they didn’t realize they’d have one,” Edelman says. “Others procrastinated and didn’t save enough to support themselves.”

A need for money is only one reason you may work after you’ve retired from a career. Another reason to rejoin the workforce for many retirees may be the unexpected feeling of boredom that comes with retirement.

“Many people have grandiose ideas of golf or traveling or gardening or engaging in whatever hobby they like, and after a few years they get bored,” Edelman says. “They miss the intellectual challenge, the camaraderie they had with coworkers.”

Retirees today see work as a vital part of their retirement, says Kimberly Adler, AARP senior vice president of programs, in a blog post on the AARP site. People want “a sense of purpose or role in society” even after retirement, she notes.

Set aside time and money for education and training

In the AARP survey, four out of 10 people who want to work in retirement said training is a key to remaining competitive.

That’s particularly true for the many people who don’t want to—or can’t—stay in the same jobs. People who were airline pilots, firefighters, or police officers, for example, often are not permitted to stay in those careers after retirement. And in other cases, people get burned out, Edelman says.

“People want to learn new skills. They want to engage in something different from what they’ve done for years already,” he says. “That’s why you see people shifting away from just a college education to lifelong learning.”

This includes going back to school, whether for a full degree or just a few informational classes, after retirement. But school usually isn’t free, so be sure you have money set aside for education costs.

Explore your options—even the high-tech ones

Although many retirees may be considering a traditional full- or part-time job, some may find the new so-called “sharing economy” is the best way to stay engaged and earn money without committing a specific amount of time.

The sharing economy allows a retiree to use his or her free time and an underused asset, like a car or an extra bedroom, to earn money. Companies such as Uber, Airbnb, and Sidecar offer retirees a way to contribute to society, help reduce boredom, and may help retirees earn extra money, all without requiring much training or a set schedule.

You can cook meals, make deliveries, babysit, walk dogs, or share your power tools.

“There is virtually [an] endless list of ways you can use resources you already have and turn them into opportunities,” Edelman says.

“You set your own hours, and you have better control over what you’re doing, so for many people it’s a better alternative,” he says.

Save, save, save

Although some people working in retirement need the money to live, a Bankrate study found that only about 15 percent of retirees are living off the money they earn in retirement. The rest are saving that money.

Edelman says that this is a good thing. Many people will need a backup plan because they won’t be able to work as long as they think after retiring. Illness or a family member’s needs may mean people who thought they could work well into their 60s or 70s can’t actually continue working.

“I would hope people are setting aside this additional income for the future because one day they will stop working, probably due to health. They will need money to pay bills when they’re no longer able to earn money,” he says.

If you’re not sure in which kinds of savings accounts or stocks you should invest, be sure to consult with a professional financial planner to assess your situation and determine the best solution for you.

Megan Craig is a Chicago-based journalist and communications professional who writes mostly about personal finance and consumer issues. She is a former reporter and editor for the Chicago Tribune. Follow her on Twitter @megcraig1.