Like any software application, over time file 'fragments' build up in QuickBooks, causing performance to degrade and, if allowed to reach an excessive level, serious corruption or loss of your QuickBooks file. When you run a backup within QuickBooks, part of this backup includes a File Verification utility that finds and fixes these fragments. If you are running one of the popular backup programs to backup all of your files, this file verification process does not run, since QuickBooks doesn't "know" that it is being backed up.  Press the F2 key on your keyboard with QuickBooks open and on the left side you will see a 'DB File Fragments' line. If this number is greater than 10, you need to 

If you run a QuickBooks backup (from the File_Create Backup menu) and click on the Options button in the pop-up window, you will see a screen that shows the verification options 'Complete verification', 'Quicker verification' or 'No verification'. We recommend that you leave this set to 'Complete verification' and then set where you want to backup your files and how often you wish to be reminded. Then do a backup when you are reminded.

Alternatively, you can periodically run the Verification utility form the menu item File_Utilities_Verify_Data. But there is no reminder for you to do so.

As a final note, if you are not running one of the full-computer backup utilities like those cited above, you should regularly backup your QuickBooks files to a flash drive or external disk drive and take the backup offsite.  We have seen clients diligently backup their QuickBooks file to a local drive or a flash drive and then leave the flash drive inserted in their computer.  In the event of a fire, flood or other disaster you'll be losing both your active QuickBooks file and your backup!