As it happens, I tested the backups at the site I worked at today
I have a little fun once a month or so asking my employee responsible for the backups to restore one of my files from around three weeks before..... To date she has never failed.... But it's nice to keep her on her toes......

But let's _never_ expect a home user to even consider a backup..... They never, (ok, I lie a little.... ), lose files at work..... How could they lose them at home?