Choose Tools - Options - Load/Save - General.
Mark Always create a backup copy.
If the Always create a backup copy option is selected, the old version of the file is saved to the backup directory whenever you save the current version of the file.
Choose Tools - Options - Load/Save - General.
Mark Save AutoRecovery information every and select the time interval.
This command saves the information necessary to restore the current document in case of a crash. Additionally, in case of a crash Office tries automatically to save AutoRecovery information for all open documents, if possible.