This is an old thread but it seems like this app is still the most appropriate for my request so I’ll post this here. I’m basically looking for the same thing outlined in this thread.
One of the first questions people generally ask when someone hits lvl60 is “how long per day did you spend doing reviews?” Incidentally, this is also the question I get asked most by friends when I talk to them about WK in general. Since the egg timer is already keeping track of each discrete review session, it seems like a best fit for taking it a step further to store and analyze that session data.