From this transcription of a talk by Charlie Munger:

And the one thing that all those winning betters in the whole history of people who’ve beaten the pari-mutuel system have is quite simple. They bet very seldom.

It’s not given to human beings to have such talent that they can just know everything about everything all the time. But it is given to human beings who work hard at it—who look and sift the world for a mispriced bet—that they can occasionally find one.

And the wise ones bet heavily when the world offers them that opportunity. They bet big when they have the odds. And the rest of the time, they don’t. It’s just that simple.

That is a very simple concept. And to me it’s obviously right—based on experience not only from the pari-mutuel system, but everywhere else.

And yet, in investment management, practically nobody operates that way. We operate that way—I’m talking about Buffett and Munger. And we’re not alone in the world. But a huge majority of people have some other crazy construct in their heads. And instead of waiting for a near cinch and loading up, they apparently ascribe to the theory that if they work a little harder or hire more business school students, they’ll come to know everything about everything all the time.

To me, that’s totally insane. The way to win is to work, work, work, work and hope to have a few insights.

How many insights do you need? Well, I’d argue: that you don’t need many in a lifetime. If you look at Berkshire Hathaway and all of its accumulated billions, the top ten insights account for most of it. And that’s with a very brilliant man—Warren’s a lot more able than I am and very disciplined—devoting his lifetime to it. I don’t mean to say that he’s only had ten insights. I’m just saying, that most of the money came from ten insights.

So you can get very remarkable investment results if you think more like a winning pari-mutuel player. Just think of it as a heavy odds against game full of craziness with an occasional mispriced something or other. And you’re probably not going to be smart enough to find thousands in a lifetime. And when you get a few, you really load up. It’s just that simple.

When Warren lectures at business schools, he says, “I could improve your ultimate financial welfare by giving you a ticket with only 20 slots in it so that you had 20 punches—representing all the investments that you got to make in a lifetime. And once you’d punched through the card, you couldn’t make any more investments at all.”

He says, “Under those rules, you’d really think carefully about what you did and you’d be forced to load up on what you’d really thought about. So you’d do so much better.”