Mark Zuckerberg has one rule for hiring at Facebook.

How does this apply to the jobseeker? Well, Facbook is a pretty successful company, and it seems that if you can fulfill this one requirement of Zuck’s, you can increase your value on the job market.

What’s the secret? Be someone others would want to work for.

Facebook founder and CEO Zuckerberg – who is thirty years old and worth $34.8 billion – recently held a Town Hall type Q&A at Mobile World Congress in Barcelona, reports CNN, and shared his one rule.

“I will only hire someone to work directly for me if I would work for that person,” Zuckerberg said. “I think this rule has served me pretty well.”

He went on to stress the importance of a keeping a small team, saying, “Facebook is not a company for everyone in the world.” And, in response to a query about delegating to other people: “The most important thing is to keep your team as small as possible. [Facebook] serves more than a billion people around the world but our team has fewer than 10,000 people. It’s only possible because of modern technology. Big companies get bloated.”

This isn’t the first time Zuckerberg has dropped a pearl of business wisdom before a crowd. Last year, at his first ever public Q&A session at Facebook’s California headquarters, he answered the question of why he wears the same grey t-shirt every day.

Zuckerberg explained that there are, in fact, several of the same shirt, which is good because otherwise he’d be kind of smelly. (He doesn’t actually wear it every day either. There are many pictures of him wearing different shirts, but he does usually look like he’s wearing some variation on a theme.)

He then went on to say:

“I really want to clear my life to make it so that I have to make as few decisions as possible about anything except how to best serve this community. There’s actually a bunch of psychology theory that even making small decisions, around what you wear or what you eat for breakfast or things like that, they kind of make you tired and consume your energy. My view is I’m in this really lucky position where I get to wake up every day and help serve more than 1 billion people, and I feel like I’m not doing my job if I spend any of my energy on things that are silly or frivolous about my life, so that way I can dedicate all of my energy towards just building the best products and services and helping us reach our goal and achieve this mission of helping to connect everyone in the world and giving them the ability to stay connected with the people that they love and care about. So, that’s what I care about. Even though it sounds silly that that’s my reason for wearing a grey t-shirt every day, it is true.”

He then pointed out that others throughout history have done the same, like Steve Jobs, who was usually wearing a black mock neck.