David Allen recently wrote (no link available):
I'm lazy and I don't want to think about anything more than it deserves. So my quest became to find the best and most efficient ways to think about things as little as possible. What I found was that by asking a few clarifying questions, and putting the answers in a trusted system, I was able to use my mind more creatively and more strategically for the kind of stuff that really did deserve my mental horsepower.
Using a good system for capturing standard processes allows you to delegate routine thinking to your system, thus freeing up your mind for hard thinking. Contrary to popular belief, a good organizational system enhances creativity.
Most people use a calendar this way. They put appointments and deadlines on their schedule, rather than trying to keep it all in their head. Instead of thinking about when a meeting is scheduled, for example, they focus on preparing for the meeting, or doing something else entirely. By getting the basic information about their schedule on the calendar, it frees them up to think about more important things.
But most people don't appreciate that this method works just as well with tasks. By taking the list of next actions out of your head -- which is usually an impossible thing to keep in your head anyway -- you free up mental RAM for something else. This is particularly true with routine and standardized tasks, which may require little mental energy to do, but tremendous mental energy to keep straight in your head.
And getting tasks into your system minimizes waste. Managing tasks mentally adds little value, and does so at the expense of higher value thinking. It's like searching for a tool versus using the tool to make something.
D. Mark Jackson