I was live witness to a real-life horror story - that of my sister's thesis.
This was back in the days of DOS, and a 486 laptop. She had 95% written it(several hundred pages), and the laptop crashed, taking out the HDD at the same time.
Her words to me when I suggested(before the disaster) that she should have a backup on floppy disk or at least a printout still remain etched into my memory: "Why?! It's saved on the computer!" - my sister and I did not get on all that well as teenagers, so I never took it any further, and guess what happened?
Now, even though I did not exactly like my sister back then, I still would not have wished that on anyone including her - to see the anguish and despair on her face - I still remember it, and there was NOTHING we could do to fix the problem - we even took the laptop to data-recovery service of the time(costing $$$ just to look at it), and they said that a power surge had taken out the motherboard and the HDD electronics, and so there was no way(at that time) to access the HDD again - dead duck.
A very painful lesson was learned that day, and she had about two weeks once we got a new computer, to re-write her thesis from the very beginning from her memory, but all that pain for the sake of a couple of floppies and maybe $5...
With respect to PICAXE code, which too can represent hours and hours of effort, I employ a simple multiple-redundant backup method: (1) Backup to another folder on the working laptop, (2) backup to a floppy disk, (3) backup to a USB-drive, (4) backup to my server, (5) a hardcopy printout of EVERY code variation, and finally (6) backup to this machine I write this post on tonight.
Anyhoo...