I was just about to mention this!I dunno the schedule, but it does save drafts. I can't answer that.
You can save drafts manually:
View attachment 8055
It's in the floppy disk icon menu. You can also delete your drafts. I do that when I decide against posting. It's a trivial amount of database space, but I know what it's like to pay hosting bills! ;-)
Gremlins?.....which begs the question why...