I make "regular" backups of my machines. (Don't we all?

)
I have found that it is "best" to backup a disk that is not being used at all.
So I boot from a live CD.
I mount the partitions to be backed up.
I mount the backup device.
I make the backup using
rsync (slow the first time [hours], but very fast subsequently [minutes]).
The first time I did this, I removed my HDD, and put in a clean one, and attempted to restore from a supposed catastrophic failure: The result was interesting - it was much more difficult than I had anticipated, but worked in the end, and I learnt a lot.
If you don't
test your backup strategy, you do not know if it will work when you
really need it. You have been warned. Better an afternoon testing than a lifetime's regret for personal data that is lost forever.