Many time-management books recommend you do a detailed “time log” to find out how you really use your time. They recommend you keep a record of every activity, with 15-minute precision.

These have always struck me as a little compulsive, without much obvious benefit. I thought keeping track of my activity with that much detail would really bog me down. So, I’ve resisted doing them.

But a book I read (The One-Life Solution by Henry Cloud) persuaded me to try one for a few days. I didn’t learn too much new about where I spent my time. But much to my surprise, I learned that a time log can boost productivity.

For example, at the time I wrote in 2.5 hour blocks. Because I was being meticulous to note interruptions (to eat or play with the cats), I also noticed how far I was through my time block. One day I noticed I had only 30 minutes left, and I wasn’t close to finishing what I needed to do. Another time, I would have been caught by surprise and I probably would have messed up the day’s schedule. But because I was monitoring the time, I noticed the problem while it was brewing, so  I was able to do a few minutes of “thinking on paper” about how to best use the remaining 30 minutes. No problem! The day went as planned.

In another case, I noticed that I did a few 5-minute side activities in a row, when I was supposed to be starting a new task. I did a couple of minutes of “thinking on paper” about how to get started, and was able to dig into the new task with no more foot-dragging. The transition was quicker and easier than usual.

Just by doing a time log, I became more aware of distractions and floundering while they were occurring. When I notice a problem, I am motivated to fix it. So, doing a time log actually helped me be more productive.

Here’s how I did it (so it wasn’t too intrusive): I kept a pad of paper with me, and every time I changed activities I updated it. I wrote down the new time on a fresh line, and wrote in (or corrected) what I had been doing in the previous chunk of time.

I had to correct it sometimes, because I would write down what I intended to do. It turns out I didn’t always follow my intentions immediately. I would finish feeding the cats, and mark the time “8:30: Start writing,” but then I’d realize I needed to do one other chore before starting writing. That was eye-opening, too.

So, I do not recommend doing a time log to find out where you spend your time. Doing a time log changes how you spend your time.

Instead, I recommend doing a time log to help you monitor your time as a special review. Done only occasionally, this can help you find the holes in your productivity and renew your focus on getting things done.