How many of you do full (entire) backups?

I have had backups and lost stuff. How many of you have a full backup that you would lose nothing if your computer crashed or whatever? I mean no loss, not like rsync on Ubuntu, no created at time, nothing lost. If you have a backup or more than one, how do you do it? This on a per machine basis. All as per one might be maybe or might not be maybe, maybe or maybe not, maybe.