Best-selling author explains why you should invest in a 'career savings account'

Everyone knows the value of a savings account. During a crisis, or even just when an unexpected need arises, having some money tucked away means you'll have it to help solve problems.

But not many people have heard of a "career savings account," which is something Jon Acuff, best-selling author of the book "Do Over," says every professional needs.

A career savings account is a stock of assets you build up over time that gives you the stability to weather any work-related shifts. And there are always shifts.

"Everyone needs a [career savings account] because your career is going to change," Acuff tells CNBC.

"It might not have a shift as large as what happened to cab drivers with Uber but change is coming for you in some form."

Career changes could come from the outside, if your company lays you off or you get a job offer. Or they could come from the inside as you realize you want to try a different path.

Either way, you'll want to start investing in your career now, Acuff writes.

There are four areas to invest in, which he illustrates as a very simple equation:

Career savings account = Relationships + Skills + Character + Hustle

Networking , learning new skills , exploring your own personal interests and having a strong work ethic, or what Acuff calls hustle, are all necessary. If you're missing one of these, the career savings account isn't complete.

For example, if you have relationships, skill, and character but lack the drive, then you could end up being like a one-hit-wonder band or a NFL draft pick that doesn't live up to potential.

If, on the other hand, you're lacking the right relationships, you can get stuck: You have potential but you may not be able to realize it.

The key is to develop all of these traits so that your account is there to help with the shifts heading your way. "There are always career waves," Acuff writes. "The well-prepared ride them, the ill-prepared are swept away by them."

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