How Do You Know When an Idea Will Turn Into a Novel?

How do you know when an idea will be a short story, or how does it turn into something longer? People quite often ask. Honestly, it's just kind of a feel, having done it a lot. In some ways, if youi a short storyis a bit like getting really tightly focusing a lens down onto a story. And so usually it comes from that what sort of vive of story i'm going to tell. But i don't always get it right. The third nevella in that ongoing nevella series comes out in december.