I was just on Facebook and saw an author mentioning that they’re writing six short stories to serve as an introduction to their main series of novels.
My immediate thought was, that might be a waste of time.
I as a reader am a novel reader. I don’t seek out short stories or novellas. I did recently find myself reading novellas by two authors I like (Kristen Britain and Ilona Andrews) because that’s what they’d released recently and I am constantly starved for more material from what I consider top-tier authors.
They were fine, but if that’s all they ever published again, I’d stop reading them because they wouldn’t be meeting my needs as a reader.
And for a new author? Someone I’ve never read before? I’m not going to buy that 99 cent short story or novella. I won’t even look at it because I’m not a short story or novella reader. Give me a free or 99 cent novel of yours and I might check it out. (Might. I’m weird so rarely buy books on those kinds of sales and still read mostly in print.)
And, yes, there are readers who cross over between stories of all lengths, so writing a short story or novella lead-in to your world might be an effective strategy to bring in a certain percentage of readers. And if you have an opportunity to be in a box set or themed anthology it might make some sense to participate to expand your exposure to new readers.
But, honestly, I would say that if you’re going to commit yourself to writing 50,000 to 100,000 words in a world that you stick to the same general story length and type you’ve already written so that you can pull the readers you attract to one of your titles through your entire series.
As always, YMMV, but something to think about. At the end of the day it all depends on your audience and knowing what they will/will not buy from you.