By chance, shortly after reading Mark Friedenbach's parting message, I saw this on Seth Godin's blog:

Is it meeting your needs…

Or merely creating new wants?

Is it honoring your time or squandering your time?

Is it connecting you with those you care about, or separating you from them?

Is it exposing you or giving you a place to hide?

Is it important, or only urgent?

Is it right, or simply convenient?

Is it making things better, or merely more pressing?

Is it leveraging your work or wasting it?

What is it for?

Good questions to ask, especially of any habit one has not reexamined in a long time.