All I really need to back up is my personal data, photos and music. Also my TB profile and e-mails. If I were to have a complete crash I would take advantage of the situation to do a clean install although trying to recall all my preferred desktop preferences is a royal pain.
If you use LuckyBackup, Grsync, BackInTime or similar, you can set it to back up your /home directory and have all that personal data plus your configuration settings for TB, Firefox, etc. Just make sure the hidden files get backed up.
Because of this, I never hesitate to re-install from the latest LiveCD at the drop of a bit. It only takes minutes, gives me a chance to refresh the partitions according to my latest skillset, and if I need to do so, I can pick and choose the parts and packages I want to put back into play.
It sure as h-e-double-hockey-sticks ain't Windows in that regard!
