Is there a feature or tool available that you can run against a server and
get an estimate on how much data will be backed up? Restore has the Estimate
option.

I have a client that backs up file servers over a WAN link and some nights
the backup doesn't complete in the window allowed. They  want a way to know
if the backup won't complete that night.

They are using TPC Data agents on the servers, but that just reports on last
change date > 1-day, 7-days,. and doesn't appear to be too accurate.

TIA,
Bill Boyer