"(…) Working too hard is actually the easy way out. For entrepreneurs, it’s often easier to keep working than to take a break, even when you know you should."
"Yet the spacing effect is really tough to put into practice because taking pauses and stretching timelines out feels like idleness, like you’re not being productive. Why relax when you could be doing something, anything, to improve the business? It feels more logical to keep pushing yourself even though you don’t feel like you’re moving forward anymore."
"This is the psychological trap that’s absolutely essential for you to avoid, where the patience and perseverance to rest comes in. Without rest, you not only risk decreased productivity, you’re increasing your vulnerability to long-term burnout." 
"Lately, I’ve been hearing something that disturbs me. A lot of entrepreneurs onstage have been bragging about not sleeping, telling their audiences about their 16-hour days, and making it sound like hustle-at-all-costs is the way ahead. Rest be damned, they say — there’s an endless amount of work to do."
"I think this message is one of the most harmful in all of business. Sustained exhaustion is not a rite of passage. It’s a mark of stupidity. Literally. Scientists have suggested that scores on IQ tests decline on each successive day you sleep less than you naturally would. It doesn’t take long before the difference is telling."
"People pulling 16-hour days on a regular basis are exhausted. They’re just too tired to notice that their work has suffered because of it." 
Sometimes you do have to work super hard. Sometimes you do have to pull all-nighters. Sometimes there are periods of 14-hour days, 6 days a week. We’ve been there. We’ve also burned out. We have also hit a wall with products and companies that were not going anywhere and resorted to keep pushing endless hours. And when the crash and burn came, it was all the worse.
Working hard ≠ working too hard.
You can crank it up to 11 for a period, sometimes that’s the way it goes. But living cranked up to 11 won’t compensate for any problems. It will make things worse. You won’t go faster, it will slow you down. Worse code, more bugs, more QA, worse decisions, less traction, worse team morale. And one day - could take weeks, months, years -, your fuel tank is empty. Empty fuel tank + troubled product|company = burnout.
Is it worth it?
Take a step back, let it breathe. Think. Sleep, eat, work, play, repeat.
If we’re in this for the long run, then we have to take care of the engine so that it lasts the entire race.