As Dave says, there's a good chance you will have nothing to worry about ... for a while (which could be years). Still, for suspenders-and-belt security, cloning your hard drive might not be a bad idea (once a week? once a month?)

I used to use a program (free) called XXclone and I loved it. Unfortunately, the author/CEO of the company passed away a while back, and the program no longer works.

I'd be interested in what other folks are using, too.