By default, Microsoft word automatically saves your current document after every ten minutes. This can be changed. It is also possible to create backup of files automatically.
Steps:
Select Options command from Tools menu.
A small dialog box will open.
Select the Save tab in the dialog box.
Check the option "Always create backup copy". This sets your word to create backup copy of file each time, you save document.
Click the "Save Auto Recover info every" check box and enter the time in minutes.