If you work on something for five years, that’s more than 20 percent of your productive work life. Most people don’t think about that, but it’s the main thing I think about. I think about it all the time, much more than money. Because the only thing we can’t make more of is time.
Dean Kamen, in the fascinating fly-on-the-wall book by Steve Kemper, Reinventing the Wheel: A Story of Genius, Innovation, and Grand Ambition (via jackcheng)

