Here’s a little video we did about our archiving process. This is what everyone should do when you’e finished a project. The key is making files and stems of each part in the session so that you can recreate the work without relying on the DAW or the plugins being available at the time that you need them.
Also, understand that backup and archiving are different. Backup is making sure you can recover from immediate disasters while you are working on a project. That’s difficult and requires some planning. Archiving, on the other hand, is preserving your work for future use long after you’re done with the project. That is much more difficult and more important still.
Remember that your storage medium won’t last forever either, so use a RAID, and copy forward all of your work as new, larger drives become available at reasonable cost.