Always do backups to more than a single media (whether that is a another hard drive, RAID system, tape etc.). A distributed risk is always the better approach.
Many protest and state this is simply too much overhead and work. Perhaps, perhaps not. Just pull the plug on the hard drive in your machine and learn what you have left of all your work. Probably very little if at all, unless the drive can be restored. For the latter purpose, backups (which are current) are indispensable.
You might do the exercise mentally so as not to physically destroy the drive. Just pretend your disk drive no longer exists. Lessons like this are invaluable if you follow up before your drive(s) actually crash. Not afterwards.