With Jack Dorsey set to juggle dual jobs - both in the capacity of a CEO for Twitter and mobile payments outfit Square - naysayers are painting a not-so-pretty picture of what he can expect running two companies.

One man who is in the same boat as Dorsey is Elon Musk as he manages both SpaceX and Tesla Motors simultaneously. Musk is the CEO of the electric car making company, as well as the space transportation company.

With Dorsey being appointed the CEO of Twitter, he joins the ranks of Musk as he gears up to multi-task. An experienced hand at juggling several tasks, 44-year-old Musk has now doled out some valuable advice for Dorsey.

With a large chunk of the Tesla and SpaceX CEO's time being consumed by engineering challenges, Musk did not wax eloquent on the proposition of undertaking a dual CEO role.

"I wouldn't recommend running two companies. It decreases your freedom a lot," revealed Musk at the Vanity Fair summit when asked on his thoughts on the challenges of managing to companies.

The entrepreneur divulged that nearly 70 percent of his day revolves around design and engineering. According to Musk, approximately 2 percent to 3 percent of the time is invested towards press commitments such as appearance at various events.

This percentage too is a lot according to Musk and he intends on reducing it further.

"I'm going to reduce it even further to only about 1 percent of my time," noted Musk, but despite the challenges he would not give up his position.

To give Musk his due, he runs companies that comparatively have higher stakes and different challenges when likened to those faced by a microblogging site such as Twitter or a payments system such as Square.

It would be interesting to see how Dorsey responds to this advice. The Twitter and Square CEO seems optimistic of handling the role efficiently.

I've been CEO of both companies for over 3 months now. I have the smartest, strongest, and most determined leaders in the world on my teams.

— Jack (@jack) October 5, 2015