For CEOs - The Sunday Night test
"This is always a test of a good CEO. You look at what you’re doing Sunday night. Half your calendar should be free. If not, you’re mostly reactive, not proactive. You’re not leading the team where it needs to go. You’re not helping the team succeed. You’re reacting to emails and phones calls.  "
--

– Vinod Khosla

( As quoted in the Forbes article here )

An Indian-born American businessman and venture capitalist. One of  the co-founders of Sun Microsystems, and served as its first CEO and Chairman in the early 1980s. In 1986, he became a general partner of the venture capital firm Kleiner Perkins Caufield & Byers, where he remained through the early 2000s. In 2004 Khosla formed his own firm, Khosla Ventures, which focused on venture investments in various technology sectors, most notably clean technology.