I had never thought of this type of data tracking, but now that you mention it, that functionality would be extremely useful...
You can use the Properties "SW-Last Saved Date" in a table on a drawing sheet and calculate time spent from that. I'm not sure how it could be done on the part or assembly level. I'd bet you could find/write a macro that would add a row to a general table on the drawing and then add time and date stamps to the columns. Add a little excel formula skills and voila' - time tracking...
You might find an add-on product that will do this as well. If there isn't a solution out there - there should be...
*AHEM* API ninjas... HINT HINT!
In an animation?
In Custom Properties?
I don't think there is really any way to determine this. How would you count it?
Parts can be edited from assemblies.
Assemblies can be driven by parts.
Drawings can modify parts.
Parts change drawings.
If you want to "impose" the restriction that "editing time" is defined by that document being the active window in SW, it's easy.
So what happens when someone goes to lunch forgetting to close their file? Or decides to work in Excel or write an email? You want some activity monitor? "Timeout" value or something?
Retrieving data ...