not always so simple...
User works all day long on an excel file on Monday. End of the day user saves it one last time before going home. Because of the known problem of excel files corupting with Novell servers the file saves corupt. Your Monday night backup runs and you backup a coruptted excel file. Tuesday morning user can not open file.
Then you decide 2 days of the research director's time or pay the $160 for the excel file recovery util.
This happened at where I currently work in December of 2000. got the demo from officerecovery.com we liked that we got to see the first part of each sheet in the excel file and purchased the full version. ten minutes latter we had the file recovered.