Knowing what changes/settings are in place that are causing the " . . It has been used in other places" error so can see if those other places can be adjusted.
For example, when trying to unassign a timekeeper from a matter, or trying to delete a project, or any number of items - that error comes up. It would be helpful if there error provided more detail - or a link to see the details of what's causing the error - so that you can fix/address where needed.
How often would you use this request?
Every time that error comes up.