There was recently a debate being had on Twitter about whether working long hours is a necessary component to having a great career. On one side, you had successful business owners arguing that their success would not be possible without working around the clock, and giving examples of well-known celebrities in the same boat. On the other side, you had successful business owners arguing that their success was possible because they took time to rest and work reasonable hours.
One of these successful business owners was Tobi Lutke, CEO of Shopify. His entire thread is worth reading, but this thought in particular caught my attention:
"For creative work, you can't cheat. My belief is that there are 5 creative hours in everyone's day. All I ask of people at Shopify is that 4 of those are channeled into the company."
There appears to be a lot of support for this idea. One popular source is the book "Deep Work" by Cal Newport. Newport proposes that focused work is the most important skill to develop, and says that we have a limit of about four hours of such work.
My own take on this is that there are many roads to a successful career, with different blends of creative and (for lack of a better term) "non-creative" work. While the amount of creative work per day may tap out at four hours, and lack of sleep affects further affects the quality of work, it's possible that success for some people was found by compensating for these concerns by putting time into areas that benefited from "non-creative" work. Success for others was found by leveraging their four hours a day of deep work into a valuable activity, and minimizing the remainder of the day spent on work.
Given these two scenarios, when looking for success, it's hard not to feel motivated to pursue the second example of those who most effectively leveraged their deep work. It likely requires significant work in understanding how to make your creative work valuable to others, but if the end result is a successful career and a well-balanced life, what more could you ask for?