Planning for Failure.
There are two distinct philosophies employed by technologists of all types: one believes that it is possible to create a highly reliable, consistent, working system. The other understands that no matter how hard you try, something will break sooner and later, so yes, do try to create the highly reliable, working system, but equally important is the planning for what to do when it fails. Sure your nonvolatile storage is reliable, but do you have a backup in case it fails (actually not if, but when it fails)? A failure could come as a mechanical event, loss through theft or accident (oops), intentional or accidental — but failure and loss nonetheless. Unless you are really really close to perfect, planning for failure is the prudent path often ignored.