Bill Gates and Warren Buffett were interviewed by Charlie Rose (I don’t know the date it aired, sorry), and in this excerpt on YouTube, Gates talks about what he learned from Buffet about protecting his time.

“The fact that he is so careful with his time” was a revelation to the young Gates, and it taught him that “sitting and thinking may be a much higher priority” than responding to the normal demands of CEO life. “You feel like you need to go and see al these people, [but] it’s not a proxy for seriousness that you fill every minute in your schedule.”

“People are going to want your time,” Buffett says. “It’s the only thing you can’t buy. I mean, I can buy anything I want, basically, but I can’t buy time.”

This is a really interesting exchange in my view, because we often think of time as being like money. It’s not just that we work X hours a day, to earn a living. It’s not just that our language jumbles the two together: we say that “time is money,” and that we “spend” time.

What I mean is that we treat time as something to invest, and treat inactivity as like an underperforming asset. Our time can’t be like the money that we’ve stuffed in a mattress: it has to be out in the world, circulating, creating value, working for us. Our calendars are like hotels: the closer you get to being 100% occupied, the better off you are.

So it’s striking that Buffett doesn’t treat his own time that way. Not that he’s unfamiliar with the idea that time is money. Berkshire Hathaway owns (among other things) Burlington Northern Santa Fe Railroad, logistics companies, insurance companies (GEICO, National Indemnity), NetJets, and construction companies. Lots of these are companies where you don’t want stuff just sitting in warehouses or worksheets, idling on the runway or train yard: the more things are moving, the more money they make. You can bet that Buffett understands this.

And yet, he doesn’t treat his own time that way. At one point in the interview, he shows Charlie Rose his appointment book (and it’s a simple paper diary): many of the pages are blank. It’s not that people don’t want Buffett’s time; it’s that Buffett values his time more than they do, because he knows that time isn’t money.