This is my first contribution to this thread, but I do have 385 (I think) stories on here at the moment.
The way I write, almost anything leaves the possibility or even necessity of further parts, so a story becomes a series. I think the longest one went to eleven parts, but that could still possibly be added to.
The trouble with this is that I still have loads of stories that could/should have further parts.
I have started Part 5 of my current masterpiece which started with 'How Fascinating' subsequent parts have been numbered 2, 3 and 4- clever eh?
When writing what becomes a series I am anxious not to become too repetitive so it is a relief sometimes to think of something that allows the story to go at a bit of a tangent or adds another character or two. That was what happened in this case because even after Part 3 I was wondering where to go with it without it just being a repeat of what had gone before.
Thanks for reading this- and maybe for reading my 385 stories!