Writing on the computer is a joy, but the ease with which we create and save our work makes us forget what a thin thread supports our archives. The accidental brush of a hand can erase a year's effort, a power outage could easily destroy a day's work, and a hard drive failure always seems to happen at the worst of times.
All of the foregoing points out the necessity of making back-up copies of your works, including those in process. Backing up has been my mantra since my first computer, with over thirty drafts and all my previously published works, was stolen many years ago. A second theft of my computer was less catastrophic because I had just cut a CD of my writing files, but still lost the drafts and outlines, notes and clippings of works in progress, along with a host of non-writing related material. That's when I bought an external hard drive on which to store everything and began storing my CD's separately. This was an awkward process for a non-OCD writer, like me, who had to schedule backup sessions so I would not forget.
As I said in the title, backing up is hard to do, but it's something every writer should do. When Apple introduced Time Machine to automatically save my files I nearly cried with joy and bought an external 2TB drive to support it. Recently I put everything on the Cloud AND still back up every few hours on my Mac's Time Machine, For really, really important files I also back them up on a 500MB external drive. Every six months I cut a DVR to keep in my car, and send a copy of all my files to my archivist at Northwestern University at the end of every year, along with my "papers" (scrawled notes, marked up printouts, letters, etc.) All this might seem excessive, but the peace of mind this grants me is well worth it. Did I mention that I am slightly OCD?
Backing up has had some additional benefits besides protection against inadvertent loss. Earlier this week I realized that two of my old stories had mysteriously disappeared from my current machine. Had I deleted or filed them elsewhere than my writing files? I began searching, first through the older files on my primary external hard drive, which contained copies from 2009 to the present with no luck. I then looked through the older back up drive that contained copies from 1998 to 2008, again with not success. Finally I went to my stack of original CDs, the ones I made when I first began saving files, some of which went back to 1995 (Yeah, I'm a packrat!) and found them. They are now restored to my current files.
I've had two complete machine failures since I started backing up and managed to restore everything because of my willingness to put in the effort to back up regularly and thoroughly. I would advise you to do likewise.