What are the habits? For me is not knowing ones capability . It is okay to make another new story but make sure you can make it without abandoning the current stories. The new story must also not be a carbon copy of the first . In short finish the current story before starting a new one. There is a minor issue of updating the story with only an update. I mainly see this in fanfiction(dot)net where I see updates promising to continue (spoiler alert they mostly don't) their work. It come to a point when I see an old fanfic that recently updated I don't get my hopes up.