From Drucker’s The Effective Executive, Chapter 2, “Know Thy Time” —
“Effective executives, in my observation, do not start with their tasks. They start with their time. And they do not start out with planning. They start by finding out where their time actually goes. Then they attempt to manage their time and to cut back unproductive demands on their time.
Finally they consolidate their “discretionary” time into the largest possible continuing units. This three-step process:
• recording time,
• managing time, and
• consolidating time
is the foundation of executive effectiveness.”
You don’t need to do time-tracking constantly, especially if you’re heads-down on a project that’s consuming all of your attention and making great progress.
But as soon as you’ve got your attention split between multiple projects, or if you feel like you’re not getting much done, then tracking your time down to the minute (or half hour block, or whatever) can be incredibly valuable. I always learn about myself and my work when I track my time, and I do so whenever things are even the slightest bit shaky.