Act Two: How to navigate that midlife career crisis

For most of us, the first part of life is a whirlwind. But by the time we settle into middle age, many of us have been slogging away at the same kind of work for years and may feel stuck in a mid-career rut.

Maybe we aren't as far along in our careers as we thought we'd be at this point in our lives. Maybe we've lost interest in our careers or yearn to do something more fulfilling. Maybe we're tired of traveling for work or answering to a boss. Maybe we're simply asking ourselves, "Is this as good as it gets?"

Senior businessman looking into future
Andy Smith | Getty Images

According to a 2014 Gallup survey, the majority of U.S. workers (51 percent) are "not engaged" in their jobs, and more than 17 percent are "actively disengaged." Gallup defines engaged employees as "those who are involved in, enthusiastic about and committed to their work and the workplace."

Not surprisingly, many people stuck in a mid-career rut fantasize about starting their own business, and some take the plunge—with mixed results, given the high rate of failure among start-ups.

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In 2014, 39 percent of Americans between the ages of 50 and 70 were interested in starting a business or nonprofit organization, according to a survey by Encore.org, a nonprofit group that promotes second careers in the nonprofit sector. In 2011, 24 percent of Americans in that age range were interested in launching a business or a nonprofit.

If you're an aspiring midlife entrepreneur, here are a few steps you might want to take before walking away from a steady paycheck at a time in your life when you probably have a mortgage and other big financial obligations.

Do a reality check. Try to envision what it would really be like to own your own business. Think through such issues as whether you'd actually enjoy working from home, as many sole proprietors do, said Jessica Sweet, a career coach and owner of Wishingwell Life Coaching.

"I work with people to set expectations about what owning a business would really look like," said Sweet, who specializes in helping midlife professionals overcome career ruts.

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"It may mean working from home in your pajamas," she added. "A lot of people need interaction with colleagues and the structure of getting up and going to work every day."

Get help with your business idea. There is plenty of free or low-cost help available for entrepreneurs, including free online webinars and courses for "encore entrepreneurs" (i.e., those over age 50), offered by the U.S. Small Business Administration.

If you are seriously thinking about starting your own business, put together a business plan and then ask for honest feedback from people who know something about running a business and ideally about the sector in which your planned business will operate, said Sweet. You may be launching a business to pursue a passion, but it's still important to think critically about your venture, she added.

"Bring your business plan to people who are more experienced than you are in business, and have your Shark Tank moment before you quit your job and have everything at stake," she said.

Scrutinize your financial situation. Determine how much your planned business needs to earn to cover your living expenses, which will help you set realistic goals for the business, said Sweet. You may also want to determine whether there are ways to reduce your own expenses as you work to get your business off the ground, she added.

"You need to look at your financial situation critically and think about how much money you actually need," Sweet said.

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If possible, set aside six months' worth of living expenses to cover your housing costs and other expenses while you work to launch your business, said Peter Miller, a certified financial planner and president of Zoe Wealth Management.

Miller launched his firm five years ago after deciding to make a career change in his early 40s. At the time, he and his wife set aside $25,000 in savings to help cover their costs as he ramped up his practice. They agreed that he would rethink his plans—i.e., get a job—if they came too close to spending down that money, Miller said.

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"If you are going to step out of your comfort zone and make a reasonable decision to invest in your growth as a person, then you don't want to put your family in financial peril," Miller said. "So put some money aside [first]."

Ask yourself whether you really have a passion for your business idea. After all, you don't want to leave a job you dislike to find yourself running a business for which you have no real passion. If you aren't sure what makes you tick, you can work with a paid coach or take a career-assessment course, among other steps, to try to figure that out.

"If you enter a new field, you are competition and potentially 'food' for those who have been in that field for a lifetime." -Henry Mulvihill, principal at Mulvihill Asset Management

"You don't want to end up in another situation that is just a job," said Sweet of Wishingwell Life Coaching. "You have to find the thing that resonates with you and makes you want to jump out of bed in the morning because, as a business owner, you may end up working harder than you do right now."

If you plan to enter a new field, realize that it can take as long as five years to get up to speed in that industry, and in many sectors you'll be competing with entrenched players, said Henry Mulvihill, a CFP and a principal at Mulvihill Asset Management. If you are launching a business in midlife, your best bet is to "stay with what you know," according to Mulvihill.

"If you are an intellectual property specialist, don't think you are going to easily succeed in real estate or in a franchise-food operation," he said. "If you enter a new field, you are competition and potentially 'food' for those who have been in that field for a lifetime," he said.

—By Anna Robaton, special to CNBC.com