There is a type of software that runs in the background and captures data on the time you spend in each application, generally specifying time spent in each document, on each webpage, etc. There are many, many such programs, with a host of different functionalities. Some integrate with LPM software as a way to bill time. I have found that using this software also helps me identify times or days when I am overdoing the multi-tasking – jumping around from one thing to another every couple of minutes.
I have not found any automatic time capture software that I have felt was a good fit for my practice in terms of value (they tend to be subscription-based), but I remain hopeful.