On Daily Routines, we profile successful leaders, entrepreneurs, artists, executives and athletes to explore their routines, schedules, habits and day in the life.

If you were to compare the leadership styles and personality between Steve Jobs and Tim Cook, the differences would be glaring. Jobs could be brash, over the top, and hot tempered. Cook, the other hand, is soft spoken, analytical and process-driven.

Nevertheless, there are notable similarities between the two leaders. They both had their own, unique management style that demanded a lot from their team, and they were both workaholics.

“I knew what I needed to do was not to mimic him,” Cook said in an interview with ESPN. “I would fail miserably at that, and I think this is largely the case for many people who take a baton from someone larger than life. You have to chart your own course. You have to be the best version of yourself.”

The Apple CEO is up early every morning, rising at 3.45am to work on emails for an hour — he gets between 700 to 800 every day. “I like to take the first hour and go through user comments and things like that, and sort of focus on the external people that are so important to us,” he said in an interview with Axios on HBO.

The thing about it is, when you love what you do, you don’t really think of it as work. It’s what you do. And that’s the good fortune of where I find myself.

Runner-Up: Tim Cook, the Technologist | Time

While it’s not clear whether Cook likes to have breakfast every morning, a 2017 New York Times profile by Andrew Ross Sorkin revealed his preference when he did — “two scrambled egg whites, crispy bacon (they didn’t have his preferred turkey bacon), sugar-free cereal with unsweetened almond milk.”

At around 5am, he’ll head to the gym (off the Apple campus to ensure his privacy) for his morning workout. “I go to the gym and work out for an hour because it keeps my stress at bay,” he said. After the gym, he’ll head to his local Starbucks to work through more emails, before heading to Apple Park.

While Cook is less flashy and lacks the hot tempered reputation of Jobs, he is well-known for his tough management style. Perhaps the most famous story of Cook’s demanding leadership is an anecdote from a 2008 Fortune profile by Adam Lashinsky, which recounted one of the CEO’s earlier days at Apple.

One day back then, he convened a meeting with his team, and the discussion turned to a particular problem in Asia. “This is really bad,” Cook told the group. “Someone should be in China driving this.” Thirty minutes into that meeting Cook looked at Sabih Khan, a key operations executive, and abruptly asked, without a trace of emotion, “Why are you still here?” Khan, who remains one of Cook’s top lieutenants to this day, immediately stood up, drove to San Francisco International Airport, and, without a change of clothes, booked a flight to China with no return date, according to people familiar with the episode.

Tim Cook: The Genius Behind Steve | Fortune

A more recent Wall Street Journal profile interviewed several managers at Apple, who described him as a demanding and detail-oriented leader. Middle managers routinely screened their staff before their meetings with Cook “to make sure they’re knowledgeable,” as a way to protect their team as well to avoid wasting the CEO’s time, as one manager put it.

“He’ll ask you ten questions. If you answer them right, he’ll ask you ten more,” said Steve Doil, who worked on Cook’s operations team in a Fortune interview. “If you do this for a year, he’ll start asking you nine questions. Get one wrong, and he’ll ask you 20 and then 30.”

In an interview with Time, Cook explained his unemotional leadership style, ““I’ve always felt that a part of leadership is conveying a sense of urgency in dealing with key issues,” he says. “Apple operates at an extreme pace, and my experience has been that key issues rarely get smaller on their own.”

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Check out more daily routines from Barack Obama, Joe Rogan, Jeff Bezos, Michelle Obama, Sheryl Sandberg, Richard Branson, Warren Buffet and plenty others.