I tend to/insist on search/(ing) for app connected with Google Calendar, because it enables you to see ,,whole" picture of your ,,time" visually (and quite reliably due to almighty powers).
For example I also sync my sleep with SleepDroid.
I hope to quantify one day ,,most" of precious time (sleep - work - play -> from Pareto law) (or elimnate ,,waste" that way).
Probaly it would be possible to estimate that all from Google/FB activity, but they don't want to share with us
That's why I will probaly use +30 min goal at beeminder for my work (Pareto once again).