In Life Is in the Transitions: Mastering Change at Any Age, New York Times bestsellers author Bruce Feiler writes about the nonlinear life, in which each of us faces dozens of disruptors. One in ten of those disruptors is what Feiler refers to as a lifequake, a massive change that leads to a life transition. The average length of these transitions is five years. The upshot: We all spend half our lives in this unsettled state. You or someone you know is going through one now.