How to Decide
Consider how passionate you are about world building. If you’re an author, your primary goal is telling stories. Will you be satisfied with showing your originality in the story more than the setting? Is there a risk you’ll get so involved in world building that you’ll seldom get around to telling those stories? Authors are well known for finding excuses not to write despite wanting to write. Will this become one? Every minute on this is a minute you could’ve spent on your writing craft or building an audience. Where does your heart lie?
It’s also important to consider how long you intend your career to be. If you’re a “lifer” and will write for decades in a genre requiring world building, then expending a lot of effort makes more sense than for someone who wants to give writing a shot and will bow out after failure, or even modest success. If you know that’s you, why invest tons of time, even if you love it? Fiction is a speculative field, but writing a book at least produces a product to be sold; building a world seldom does.
Life intrudes on our time to write. This is truer for longer works like a novel. If we don’t have time to write a novel this year, because we’re in college, or just became a parent, or something else, we can spend time inventing a setting instead. A novel takes months of continuous work to stay involved, but world building can be done in a few minutes here and there. In my case, I spent most of a decade unable to write due to first college and then an injury that made writing difficult; in the meantime, I built an enormous amount for my main world. The younger me gave the older me a great gift.
How Many Worlds Are In You?
Do world builders have the ability to create more than one great world? Theoretically, yes. Do you? Creative people try to avoid repeating themselves. The more specific an idea, the more sense it makes to exclude it from a second world. Having dragons on both worlds is okay, but if the first world is dominated by dragons who only breathe fire, cast no magic, and won’t let anyone ride them, then repeating that in another world makes us look like we have no imagination; the dreaded “formula” accusation will get hurled at us. With each world created, we further restrict ourselves. Soon we’re out of ideas. We could solve that by being generic all the time, but then what’s the point of world building?
If the first story we publish in a world begins a series, audiences may/will expect any subsequent stories set on that planet to have some connection to that initial one. This likely originates from this being what authors frequently do. If we defy this expectation, there may be some backlash. We can avoid this expectation by publishing unrelated stories on that world before a series there. One problem with that solution is that if we’re self-publishing, it’s widely believed that our careers will do best if we publish a series because readers gobble up subsequent books, so perhaps self-publishing a few unrelated short stories or a novella gets us past all of this. Or we can just ignore the issue.