At 81, you might think David Gilmour would be more than ready to retire. But no: 40 years ago, he lost an expensive bet with a friend that he would hang it up, but the phenomenally successful and wealthy serial entrepreneur (who co-created Fiji Water, among other ventures) just can’t stop finding new projects to dive into. It is what keeps him going, his peers say, and he looks it. For most, 81 is long past time to slow down, but Gilmour’s own life asks the counter questions: why slow down at all? Why stop? Why retire?