My spreadsheet of walks to work. I use a stopwatch app and pause it whenever I stop during a walk, so factors like traffic or me popping into a store on the way there doesn't affect it. I don't bother logging the seconds, because I'm not *that* quick at fishing the phone out of my pocket.
I should find more excuses for taking walks. It's kind of ironic that I'm working on getting a driver's license as I'm finally getting into the habit of walking every day.