Why this retired Navy SEAL commander has 3 alarm clocks and wakes up at 4:30 a.m.

Retired US Navy SEAL commander Jocko Willink has a habit of frequently tweeting out a photo of his watch when he's ready to take on the day. The watch face always reads somewhere around 4:30 a.m. Willink rarely needs an alarm clock anymore, but if he does, he's got three, he writes in the book "Extreme Ownership: How US Navy SEALs Lead and Win," which he co-wrote with his former platoon commander Leif Babin. "Discipline starts every day when the first alarm clock goes off in the morning," he wri...