Early in 2015, one of my company's investors asked me and my co-founder to make a choice: Pick one or the other to be CEO.

Dave and I built our company together as husband and wife--and also as co-CEOs. We'd always been on equal footing, and it felt silly to elevate one of us over the other. Luckily, the business took off around that same time, and the decision was never brought up again.

But having two co-CEOs is still viewed as an unusual setup. There's been a lot of coverage of Salesforce's move to put Keith Block on even footing with Marc Benioff as co-CEO, and much of it has focused on situations where the co-CEO relationship didn't work out.

I certainly don't think the setup is right for every company--there have been plenty of high-profile failures in the past--but there are circumstances where you may want to take the co-CEO approach.

Here's when this mutual partnership may be beneficial for a business:

When the partnership begins with a natural relationship.

Any time the title of co-CEO is forced on two people who work at the same company, but have little in the way of a relationship, it often doesn't work out.

Benioff and Block have known each other since the 80s. They've been working together as partners for the past five years, and both freely admit the title shift to co-CEO won't really change how they operate. They already had a great relationship built on mutual trust and experience.

On the other hand, I was working at Aeropostale back in the late 2000s when Julian Geiger replaced himself with co-CEOs Mindy Meads and Tom Johnson. The two of them didn't have that established, natural relationship, and it wasn't long before Meads left.

Being forced to share the CEO title often becomes a power struggle. The second your leadership becomes misaligned, things will start to fall apart.

Co-CEOs have to be able to work out issues and come to a consensus without a public debate or airing of grievances. When two people already trust and respect each other, they can disagree without undermining anyone.

When a company needs to balance maintaining a vision and delivering results.

People often think of a CEO as the person with the big ideas--the one who sets a vision and sits back to watch it play out. But a company needs both visionaries and people who can go about getting the tactical results that lead to the fulfillment of that vision.

If you look at Benioff and Block, you can see a clear delineation of responsibilities that works well for them. Benioff has the big vision, Block knows how to deliver. Block was already Benioff's COO before the move, so his mission hasn't really changed.

Most successful shared leadership roles involve some sort of give and take--a yin and yang approach that leaves everyone better off. For example, Dave likes to take more time to make decisions than I do. He likes to dive into the details and spend more time evaluating the situation.

I'm at the other end of the spectrum. I tend to rely on people's recommendations and make decisions more quickly.

Blended together, we push each other just the right amount. And generally, the outcome is better than if either one of us were making decisions in a vacuum by ourselves.

When each co-CEO is comfortable making 50 percent of every decision.

The benefit of being the only CEO is that you're in charge, and you do what you want to 100 percent of the time. People share input, and you listen to what everyone has to say. But at the end of the day, the decision is yours.

That's not how it works when you have two CEOs. And while that may rub some people the wrong way, I'm a firm believer that two heads are better than one--especially when you're making big decisions.

I run our marketing team and Dave runs finance, but we're both still heavily involved in what is ostensibly the other's department. We still provide input on decisions within different areas of the business.

Being able to work like this comes down to how deeply passionate or emphatic you are about a certain decision. There will be times when you both disagree, and one person says, "I hear you. I'm listening to what you're saying, but I disagree. This is the route we need to go." And the other will concede.

That's the tradeoff of being co-CEOs. You're not always going to love every decision that's made. But if you can become comfortable with conceding from time to time--and truly have a healthy, trusting relationship with your partner--then the co-CEO option may make sense for you.