A direct quote - - -

  I'm a tech at my place of employment. We do huge backups
of user data every night but of course if a user has a file
open or they just created a file and never saved it and it
crashes, it would not get backed up.

  A user called and said that she needed a file restored...
The tech looked in our web backup but gave up after looking
at the previous day, and going back a couple of weeks. He
called the user who informed him that she had just created
the file that morning and never saved it; her app crashed
and she lost her work and wanted the files restored from
backup.

  The tech explained that file recovery is only done on
files that had been created and saved the day before.

  The user then said "Ok then I'll call you tomorrow, thank
you" and hung up the phone.