Elon Musk has been preaching the value of 'hardcore' work to employees for over a decade, early Tesla emails show

• Elon Musk is mirroring his Tesla management style at Twitter.
• The CEO has told Tesla employees to "go super hardcore" and "ultra hardcore" in the past.

Elon Musk is following his Tesla playbook at Twitter.

Last week, the billionaire gave Twitter employees an ultimatum: commit to working "extremely hardcore" or resign.

"This will mean working long hours at high intensity," Musk wrote to employees in a late-night email. "Only exceptional performance will constitute a passing grade."

While the note spurred a mass exodus of Twitter staffers, it was a move that is all too familiar to Tesla employees.

Over the years, the Tesla CEO has been known to set lofty goals and ask for nothing short of perfection from his workers. Just last year, Musk told workers to "go super hardcore" to finish the quarter strong and later called for numerous employees to voluntarily work through Thanksgiving weekend to meet production targets for the Model 3.

In 2012, Musk asked Tesla staff to be 'Ultra hardcore'

Over a decade ago, Musk sent Tesla staff a companywide memo to with the subject line "Ultra Hardcore," Dana Hull reports in her Bloomberg Tech Daily newsletter.

"Please prepare yourself for a level of intensity that is greater than anything most of you have ever experienced before," the 2012 email read, per Bloomberg. "Revolutionizing industries is not for the faint of heart, but nothing is more rewarding or exciting, and I will personally make sure that those who produce exceptional results are rewarded exceptionally, as is fair and right."

Musk sent a follow-up email, per Bloomberg, telling Tesla workers to "Please talk to your spouses, children, relatives and friends and explain what I've said in this email."

"What it means is they will see much less of you for the next six months and there will be almost zero vacation," the follow up email, which had the subject line "The true test," read. "Please reduce time off and travel plans to the absolute minimum necessary to maintain sanity and avoid divorce."

Musk is known for his hard work ethic. The billionaire has said he's worked as much as 120 hours per week, and he's slept on Tesla's factory floor, as well as the floor of Twitter's headquarters.

He expects a similar devotion from his workers. A Twitter manager who went viral for sleeping at the company's headquarters has since become one of Musk's top lieutenants.

Speaking out against these policies or Musk, himself, can have consequences.

The "Chief Twit," as he refers to himself, has been quick to clean house, slashing over half of Twitter's staff, including several employees that appeared to diss Musk on Twitter and in company Slack channels.

The billionaire has taken similar measures at Tesla and SpaceX. Last year, The Wall Street Journal's Tim Higgins published a book that details several incidents of Musk allegedly rage-firing employees.

At the time, Musk disputed some of the claims in the book, calling them "false" on Twitter. He has also denied assertions he rage-fires employees, saying he gives "clear and frank" feedback.

Musk's leadership style is a sharp departure for Twitter

When Musk first offered to buy Twitter, former Tesla board member Steve Westly warned Twitter staffers that they could be in for a rude awakening, telling them to "put on your track shoes."

Musk's more utilitarian leadership style style represents a sharp departure from that of Jack Dorsey and Parag Agrawal.

The billionaire did away with Twitter's monthly days of rest, some remote-work options, and free lunches shortly after taking over.

This same leadership style has helped Tesla become one of the most valuable companies in the world, but whether it will have the same impact at Twitter is up for debate.

Experts previously told Insider that Musk might be out of his depth when it comes to running a social media company.

"His experience with his other companies is not translating to Twitter," said Angelo Carusone, president of the watchdog organization Media Matters for America. "At Tesla and SpaceX he's worked with a static product. Twitter is a dynamic organism. It's not a machine you can tinker with, it's a product made up of people."

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