Entrepreneur and New York Times best-selling author Grant Cardone puts in a lot of hours.
"There are 168 hours in a week. You should be working most of them," the self-made millionaire tells CNBC. "If you want to change your condition, you have to work. If you can outwork the rest of the population, you're going to get lucky."
Cardone, who was deep in debt and stuck in a job he hated before building his multi-million dollar fortune, logs at least 95 hours a week. The secret to preventing burnout has nothing to do with taking vacation or a personal day, he says: "Any time you're feeling burned out — any time you're exhausted — look for your purpose.
"People burn out for one reason: Because they're off purpose."
Think about "what it is you're here to do," he says. "You've got to find that rich part of you, the reason you're here, and go out every day and chase it down, hunt it down, and bring it into focus."
Next, zero in on your purpose by setting specific goals. You have to constantly revisit them and think big, Cardone says: "Most people quit the game because the trophy's not big enough. Me and my wife sit down and ask, 'What's the trophy now?' You make a million dollars. OK, what's the new trophy? What's the new game?"
"You do not get tired when you're having fun," he continues. "When you're winning, you don't get tired. When you're scoring, you don't get tired. The game can go on forever. But when you're not winning, you're not scoring, and it no longer matters, then you get exhausted."