Warren Buffett keeps some days on his calendar completely free of appointments. Bill Gates learned this a few years ago when the Oracle of Omaha showed the Microsoft co-founder his calendar. At the time, Buffett was teaching Gates one of his most important lessons, namely to be more protective of his own time.
In those days, Gates said in an interview with Charlie Rose, he would fill his schedule with appointments, believing that was how to use his time most effectively. Buffett made him see that saying no to most things and giving himself more free time was a more successful approach.