There’s the tendency with resolutions to want to overhaul everything at the same time. Something snaps, and so you take a long, hard look at yourself in the mirror and think, “I’ve got to do something about this,” gesturing vaguely at your under-eye bags and bitten-down nails.

Enjoyable as it is to think about how much better life will be once you’re healthy, productive and organized, overhauling everything all at once requires more willpower than it’s possible to maintain. In the 2011 book, Willpower: Rediscovering the Greatest Human Strength, authors Roy F. Baumeister and John Tierney suggest that willpower is a limited resource. Trying to resist one temptation drains self-control for subsequent tests of mental strength. The righteous fervor of a long list of resolutions ...