On a recent episode of Table Manners With Jessie and Lennie Ware, Apple CEO Tim Cook unveiled his strict daily schedule. He wakes up “probably a little earlier” than 5 a.m. each day.

“It turns out, it’s the part of the day that I can control the most,” he said on the podcast. “As the day starts to unfold, it becomes less predictable, and by the end of the day, all these things can happen to commandeer your time and intention and energy.” 

Expressing his love for the part of the day where he can “kind of block out the world and focus on a few critical things and just be silent for a while,” he adds that he typically grabs coffee and eats the same bran cereal each morning while sending and reading emails.

Despite his name, he does not cook. Instead, Cook admits on the podcast that he frequents the company cafeteria Caffè Macs. He has lunch and takes dinner home from there. “I typically go for the fish,” he says.

”Tim Cook’s 5 a.m. wake-up and consistent meals in the company cafeteria reflect discipline and intentionality,” clinical psychologist Supatra Tovar tells Fortune. “This routine likely minimizes decision fatigue, allowing him to conserve mental energy for high-stakes decisions, which is crucial for success at his level.”

Some self-help experts say that while it might seem monotonous, Cook’s schedule shows the value of having a routine. Others note it’s not all that necessary. Either way, it’s all the rage in the C-suite.

CEOs maintain similarly intense schedules. Experts are mixed on its benefits 

Indeed, Cook is not alone in his proclivity for spending each day the same way. Brian Niccol, former CEO of Chipotle and current CEO of Starbucks, told Fortune that he often wakes up around 5:45 in the morning, has a cup of coffee and a cookie, works out around 7 a.m., has a shake or eggs and sausage, and then usually drives his daughter to school before getting into the office around 8:30 or nine in the morning. 

“I look to build a lot of consistent routines,” Jack Dorsey, CEO of Block and cofounder of Twitter, echoed back in 2015. 

“Same thing every day,” he added, explaining his days start at 5 a.m. and end at 11 p.m. and involve regular meditation, a strict workout schedule, and a five-mile walk to work. 

The conceit is that given executives’ workload, time is precious and needs to be parsed out accordingly. “The way CEOs allocate their time and their presence—where they choose to personally participate—is crucial, not only to their own effectiveness but also to the performance of their companies,” Michael E. Porter and Nitin Nohria write in Harvard Business Review, adding that the CEOs they studied worked 9.7 hours per weekday on average. 

CEOs stick to said routines “because they provide structure and efficiency, enabling them to focus on priorities without distraction,” Tovar adds. While this rigidity can increase productivity, reduce stress, and help with decision-making, it can also “limit spontaneity and adaptability, which are sometimes necessary for innovation,” she says.

“It reduces your mental load,” Robin Waite, coach and founder of Fearless Business, echoes to Fortune. He adds that choosing what to wear and eat are simple choices but can also cost one time. 

Of course, some experts think CEOs should be a little more flexible. “Stumbling out of bed too early is just one of the ways entrepreneurs lose touch with their bodies,”  psychologist Sherry Walling previously warned in Fortune. “They’re looking for life hacks instead of doing some inner reflection,” she said, adding that it’s “unhealthy and unsustainable to design every day around productivity.” 

Routine can also be a part of brand identity. “The optics can’t be ignored,” Tovar says. “For some leaders, projecting discipline reinforces their image of reliability and control, though the true value depends on how well the routine supports their actual goals and well-being.”