For about 10 years I kept more or less exact track of my time because I was sure that ‘what’s not measured is not managed‘. I was actually inspired by a story (not sure it was true) of a person who was a brilliant mathematician, a prolific writer, a man of many hobbies and all that. He found time for everything because he had a rule to work 6 hours a day. Work, not sit at a desk. He had a system of recording exactly how many minutes he worked. When he got himself a cup of tea or looked out of the window he would stop the clock. As soon as the clock would tick up to 6 hours, he would stop working for the day. The morale: nurture (and count) every minute and then you don’t need so many minutes.
I have started with a little stop-watch integrated in an alarm clock. The principle was simple: every time you sit at the desk you start the clock, when you stand up – you stop it. At that time, my main priority was to finish PhD and I wanted to work at least 4 hours per day on it. It actually worked pretty well (at least the PhD got written and submitted on time).
Afterwards, I started to divide my time between several projects. I would then record, in a notebook the start and end time of each task and then enter it in an Excel sheet at the end of the week. It was rather clumsy and somewhat repelling, so for a year or two I did not actually manage to keep a very good record.
Then for many years I used the technique built in Microsoft Outlook which allows you to track time of Journal Entries. It worked as follows. Each Outlook task was assigned a category, corresponding to a project or area of responsibility (e.g. supervising thesis research). When I started to work on the task, I would drag it to the Journal. A Journal entry with the same category would be created and opened automatically. Then I clicked on the Timer icon in the entry and it started counting. I could pause the timer when I was interacted. I could also Save and Close the entry and then open it and restart the timer when resuming the work. Other entries could easily be added to Journal by pressing Ctrl-J you create a new journal entry, then enter description (e.g. “Travel”) and duration. When you drag Calendar entries to Journal their duration is automatically added. Finally, it was also good to track time that goes to answering email and other repetitive activities which are not Tasks. I created one Journal entry called Email every week and started the timer every time I worked with Email.
At the end of the week I would copy all Journal entries of that week to a separate Outlook folder and then export this folder to Excel. Subsequently I sorted the entries by their Categories and made the sum of each category.