Computer science involves effort measuring things: profiling code, tracking memory use, looking for inefficiencies in network connections, determining the number of database queries are required for rendering a typical web page in an application, etc.

I have started also measuring something else: how I spend my time. I used to just track billable time and leave time spent learning new languages, new frameworks, writing experimental code, etc. as unmeasured time. I now use a time tracking application on my Mac Book to track 16 different categories (billable, and learning/research - I also track time on Reddit, Slashdot, etc.) The overhead for these measurements is probably about 2 or 3 minutes a day, plus a few minutes to look at time spent at the end of a day, end of a week, etc. For me, this is useful information.