"Quitters never win, and winners never quit."

I'm developing a list of famous terms and quotes I don't like, and this one by lauded football coach Vince Lombardi has earned a spot on it. People often repeat this particular sentiment with the intent to encourage perseverance and the grit to keep going even when things are tough, which admittedly isn't a wretched idea.

But even setting aside the harsh fact that life isn't always fair and good, deserving people sometimes never achieve what they give everything for, and real leaders accept quitting when it's warranted.

Examples of quitting in action

Serial entrepreneurs are great examples of quitting with good cause. They routinely exit their companies and start over with something new. And when they see that a venture is starting to fail, once they've done all the smart things they know how to do to make it work, they're willing to admit the failure and move on.

Or take investors. Sure, you want to steal from Warren Buffett's playbook and find some investments you can hold onto for years, if not decades. But even Buffett sometimes reads the writing on the wall and cashes in before things get totally bleak. And sometimes he cashes in simply because he wants his money to be available for something even better he spots.

Or maybe you're in a truly toxic company that leaves you stagnated creatively, where you don't get opportunities like you should or you are in constant emotional and logistical combat with those around you. If you're seriously unhappy or stressed and have already proactively tried unsuccessfully to shift the culture by addressing management, any psychologist worth their salt likely will tell you to give your notice, pack up and move to safer environment.

Even within a standard business day, great leaders constantly are assessing where they and their companies are. We tend to frame this positively and say that they look for more opportune ways to grow or are maximizing what works. But it's basically all just quitting what you've learned isn't giving you a good ROI anymore.

So okay. Let's agree that it's okay to quit. How do you know when to do it? You look at three areas that act like checks and balances for each other.

1. Review the data.

This one is the easiest, but that doesn't mean it's a walk in the park. Run calculations and projections, do comparative analyses, read studies or other relevant and reliable sources, do surveys, etc. Just be aware of potential biases and try to stay as objective as you can no matter what you're feeling--bring in outsiders for second opinions if needed.

2. Listen to your gut.

Instinct is actually very much a feeling based on many learned experiences you've gone through over your life, and it's pretty dang accurate a lot of the time. If your instinct is screaming at you not to go ahead, there's a good reason.

Sometimes that reason is toxic, such as if you grew up being repeatedly told you'd never amount to anything. You have to completely step back in those instances and recognize the untruths you've internalized. But if the pros and cons weigh evenly and you can at least account for internal biases as you analyze, accept that your gut is relatively smart.

3. Listen to others.

This doesn't mean just take it like a sucker punch when others are telling you to fold, because not everyone is out for you to win--some actively will work against you for their own gain. It means that others can have different perspectives about your situation based on their own experiences and expertise. Don't let your ego run so wild that you're not willing to ask mentors and others you trust what they think.

If you really do some hard inner work, you might find that the only reason you are holding onto a project or other opportunity is because you associate quitting with your personal fear of being ostracized, discomfort, unfamiliarity and insecurity. But if you set that ideology aside and evaluate these three basic areas, you'll realize that quitting is, by default, a necessary component of flexibility and forward movement.

Never be afraid to throw in the towel when doing so is a well-thought out, educated and properly supported choice.