(Yes, it's that post again. But it's always better to have one more copy of that great unfinished mod you're writing than to have NO copies, right?)
And I'd rather see another "don't forget to backup!" reminder than one more "my hard drive crashed and I lost seven unfinished NPCs, six of them half-drow and the seventh a vampire(half)". For, well, various reasons.
World Backup Day is on 31rd of March, but why wait? It's really never late to backup your stuff somewhere it'll be safe, just in case. I'm doing it myself again, right now.