I'm going to respond to your post by retroactively restating my response to dk to anticipate it...
My intention was not to discuss backup strategies; it was to point out that there may be an innocuous, well-hidden file on your Mac in which you, without particularly realizing it, have invested a large amount of time and effort and that is subject to some unpredictable corruptive force, and that even if your backup strategy is "I don't need a backup strategy," that one file may be your mind-changer.
