Jim Rohn once said, “You are the average of the five people you spend the most time with.” While there are certainly exceptions to this axiom, there’s enough truth in it that it might behoove us to pay attention. And by “pay attention” I mean “pay attention to just whom we’re hanging around with.” Let me give you an example.

I just got back from the annual convention of the National Speakers Association (and, by the way, there are few things more dynamic—and more potentially irritating—than a convention of professional speakers). While there, I heard my friend and fellow speaker Jim Cathcart say that most of his friends are self-made millionaires. Do you think it’s just coincidence that Jim himself is enormously successful?

On the other hand, I know a lot of unsuccessful speakers who hang out with other unsuccessful speakers and complain about how unsuccessful they are. Again, coincidence?

In any business (yours too, I’m guessing), the best hang out with the best. And in so doing, they bring out the best in each other. They raise each others’ game.

I’ve written before about how John Lennon and Paul McCartney raised each other’s game. But they also raised the game of their fellow songwriting Beatle, George Harrison. George was a relatively weak songwriter when he began. There’s no way of knowing, of course, but my guess is that he would have remained relatively weak had he not spent virtually every hour with two of the best who ever lived. By the time George “graduated” from the Beatles, he could write with the best of them. Would he have created songs like Something, While My Guitar Gently Weeps, or Here Comes the Sun had he not spent most of his time with John Lennon and Paul McCartney? I seriously doubt it.

So who are you spending most of your time with? Have you really thought about it? Most of us don’t. We spend time with whomever happens to live next door to us, or whomever happens to occupy the next cubicle. We don’t actually seek out the people who might move us ahead in the world, move us closer to our goals. (Of course, most of us don’t even have goals. But that’s for another time.)

I’d like to suggest that you invest an hour or two and give this some real thought. Where do you want to go, and who do you need in your life to help you get there? There are many types of people you may want to consider, but there’s one person whom I think is absolutely vital for you to have in your life.

You need to have a smart person who disagrees with you.

A smart person who disagrees with you challenges your beliefs and assumptions. He or she compels you to defend your ideas rather than just assert them. He or she forces you to think. And that’s never a bad thing.

Be conscious about the people you bring into your life. They say you can’t choose your family, but you can choose your friends. Choose wisely.