From someone whose only wisdom in this case was to listen to a friend.

About a year ago my friend Michael convinced me to get an external hard drive for back up.  Without that back up, when my hard drive crashed last week a major pain in the neck would have been a catastrophe, with many years’ worth of writing and research either lost or rendered very difficult to get.  My computer repair people said they could usually retrieve the information off a crashed disc – but that it was pretty expensive to do.

Moral: If you do not have an external hard drive or equivalent, get one!  They aren’t very expensive.  My Costco one was about $100.  I think less.  It was easy to use.  Mac’s Time Machine can do the rest, and so can SuperDuper.  Easy. Even for me, a computer doofuss.