Sleep the amount of time your own body requires, preferably while hugging your partner. Spend time with your kids and grand-kids. Take a nap when you need it. Work when you must, and work hard when you do. Work really hard, in fact, but at tasks that matter - the ones that add value for your clients and customers. And if that takes, oh, more than 10 hours a day, you're probably doing something wrong. Then: go home, have a drink, eat dinner and enjoy the company of the ones who really matter - your friends and family.
Excellent summation.