I'm currently chewing on a dilemma I hadn't thought about before, but which many authors now face.
Back in the not-so-old days, when self-publishing was a rare and futile undertaking, I imagine that most authors wrote sequels when their agents and/or publishers suggested that the time was right. Now that so many of us are publishing our own novels, what conditions must be met before it's time to publish a sequel? How many readers do we have to have for the original book? If we have relatively few readers, but many of those readers have expressed hope for a sequel, do we satisfy these faithful supporters sooner, or wait for a larger audience?
One compromise would be to make sure the sequel can stand alone. But I've never liked sequels (or later books in a series) that spend a lot of time recapitulating the first book. And in the case of my science fiction novel Twin-Bred, it's either recapitulate, or write a good second story for those who've read the first. I have the latter (I hope) in rough draft. I have another unrelated rough draft -- in another genre, even -- to edit as well. Which should have priority?