You've probably heard some productivity expert talk about the importance of making a to-do list, a schedule, or at least a tentative plan for the day.

It makes sense — when you get into work in the morning, you don't want to spend an hour trying to figure out what to do first.

And yet, sometimes, all that planning and scheduling can work to your detriment. Which is why they're best used in conjunction with the "do it now" rule.

The rule is the creation of Josh Zerkel, the director of global community and training at Evernote and a certified professional organizer. When I met with Zerkel in May, he said he teaches the rule to many of his clients.

It's simple enough, Zerkel said. "If you can do something right now in the moment, without having to close it and then reopen it again later, get it done now."

Consider Zerkel's rule an alternate version of the "two-minute rule," which is the brainchild of bestselling author David Allen: If a task will take two minutes or less to complete, you do it now.

Zerkel said, in his view, it doesn't really matter if the task will take two minutes or five — if you have time to do it right now, get on top of it.

The "do it now" rule works for two key reasons.

For one, it prevents procrastination. "I'm not a big fan of look at your stuff, review it, methodically plan it," Zerkel said. "If something is short, just take care of it."

This is something I'm constantly guilty of. I'll put a time on my calendar for sending a quick response to an annoying email; but by the time I reach that point in the day, I'm exhausted and end up putting it off until the next day.

The second reason Zerkel said the rule works is that finishing even a small task "builds a sense of productivity and momentum — I'm getting stuff done! — which can lead you into getting to the bigger things that might be more challenging."

Once you fire off a response to that email, or sort through the pile of mail on your coffee table, or whatever it is that's been hanging out on your to-do list for too long, you'll feel motivated to tackle something else even bigger.