On a standard to-do list, everything has equal visual priority. Naturally, some things will take longer than others. We know this, but the to-do list format doesn't provide a quick read. It's just a list.

With time-boxing, you estimate how long you think things will take and plot those chunks of time out on your calendar:

  • Plow through emails: 30 minutes.
  • Create PowerPoint deck for Friday's presentation: three hours
  • Submit expenses from last work trip: 20 minutes

If you're new to time-boxing, you might not get the estimates exactly right at first. Adjust as you go. You'll learn to be realistic about what you can accomplish in a given period of time. Remember that you're only human, and you can't be 100 percent productive all the time. You might lose time to chatting with colleagues, eating food, or going for a 10-minute walk to clear your head. You don't necessarily need to schedule all those things in your calendar, but leave some wiggle room so you have a little flexibility.