Mac: It's easy to let the number of Mac apps you have open at any given time spin out of control. Quitter is an app from Instapaper developer Marco Arment that will quit or hide any app you want after a period of inactivity. If you find yourself wasting too much time on certain apps, say Twitter or Slack, then Quitter's an app that can take away the temptation to check in every few minutes. If you don't open an app for a select amount of time, Quitter will hide or quit that app so that you don't think about it. The "out of sight, out of mind" principle doesn't necessarily work for everyone, but if you find yourself wasting time with certain apps just because they're open, this might help you out.