Most people don't back up their computer information.  Why is that?  Because they think they will never lose anything or have a system failure that destroys all their data.  Even when a backup plan is in place often users forget, don't know how, or don't want to take the time to backup their data. 

Planning

Do you have a means to reload preinstalled software?  Depending on the manufacturer or provider of your PC, laptop, server, PDA, etc. you may or may not have what it takes to reinstall software that was preinstalled on your device.  When buying a new device always choose to receive any and all resource, operating system, drivers and related CDs with your purchase.  Some vendors only offer these as a part of their support.  If that is the case you might want to consider another vendor.

Example:  Dell optionally provides an operating system CD and a resource CD.  You should always elect to receive these since they are a zero cost (at this time) option.  When ordering other preinstalled applications Dell will always include the appropriate CD for reinstallation of that software.

What should be backed up?  If you have the ability to reload preinstalled software, then all you need to backup is information you add to your computer.  This would include email, documents, spreadsheets, accounting data, your own application data as well as the current configuration of your device.  If you don't have the ability to reload preinstalled software then you will need to backup everything on your device.  Backing up everything will more space than just backing up your own information.

Example: Most PCs come with one hard drive (designated as the C: drive).  Most people put their documents and spreadsheets in the default "My Documents" directory.  But, your Outlook or Outlook Express email and address book data is kept somewhere else.  Quickbooks defaults to keeping your company file in a subdirectory of the "Program Files" directory.  These user data files might account for less than 1 GB of your disk space while the operating system and other installed application software might account for 5GB to 20+ GB of your disk space.  So if you can reload your preinstalled software then you only need to back up the 1 GB of user data.  If not, then you need to back up the entire hard drive with 6 GB to 21GB of data.  That will require a much larger backup volume.

What type backup will you use?  External hard drive? Writeable CD or DVD? Tape drive?  Zip drive?  There are many choices.  A decision will require you to consider the cost of the backup device, the backup media, the lifetime of the backup media, the size of the backup media, how fast the device can back up your expected amount of data and how much time you want to spend with each backup.

Here are some recommended ways to manage backups.