Wow - 15 hours writing a Word doc without saving at least once?
Epicfail.
He had, but when Word had crashed it brings up the recovered files, and Alex opted to save the wrong one. I've done it before.
Which is now when I'm writing a long document I save it every 5 minutes, and then every half an hour or so, I'll save it as docname-v2, and then v3, etc. I end up with about 20 versions of the file on my computer, but if any corrupt I can roll back to a previous version and I haven't lost everything.
As for back ups, best bet is to back up to another hard drive, and then back up to disc or even online somewhere from this backup drive.