You can track time spent on each work product entry for each associate and type of task.  This feature is engaged by setting the Billing/BillingMethod in the System:Settings screen to Logging.

This feature changes the History screen to display the following:

This allows each associate to assign a code and length of time for each entry in the history.

Also as part of the history you can display a summary of the time by selecting the Billing tab in the History screen:

This displays a summary:

You can obtain breakdowns by selecting the options shown on the listing at the right of the screen.