I was just wrapping up my interview with John Hendricks, the executive chairman of Discovery Communications, when I asked him if he had any last thoughts, something we had not covered in going over his memoir “A Curious Discovery: An Entrepreneur’s Story.”

“Don’t assume your first job is going to be your career,” he advised.

That seemed an odd thought coming from a man who spent more than 30 years in one place building up a company that now is worth more, on paper, than Marriott International or General Dynamics.

But I understand what he meant. When we’re young, people are always asking what we want to be when we grow up. In college, we’re pushed to pick majors. There’s a rush to decide.

The reality is that our paths are just forming. The life expectancy of an American child born in 2011 is 79, and it is climbing. It’s easy to imagine a life of multiple careers, each informing the next.

Hendricks’s message: Stay curious. Be open to the possibilities, and then follow your passion.

It’s not hard to see how that philosophy might lead us to approach life in a different way. Instead of always trying to narrow our options, what if we sampled from the buffet?

Still, there’s something to be said for longevity. Hendricks does not sound worried about the changes roiling his industry because change has been coming to television ever since he arrived. It seems plausible we will only hunger for more as we gain a greater ability to watch what we want when we want.

Serving that demand has been a preoccupation of Discovery, and nearly all media companies, for quite a while.

Hendricks told me he likes to go to Barnes & Noble from time to time just to hang out in the magazine racks. He’s not there solely to idle, thumbing through the glossies. Rather, the visits are part of his research. Each new title represents a niche audience — just waiting for its own cable channel — and new audiences are forming all the time.

“This is an exciting time,” he said.