Story length is one of those odd ducks that writers, editors, and publishers can argue about over several nights at a bar.
Here's my two cents: It doesn't fucking matter. The story needs to be as long as it takes to write the complete story. That means it can be six words or six hundred thousand words.
Thanks to trad publishing, it became an accepted myth that books need to be a certain length. As paper costs rose, trad publishers wanted longer books in order to validate higher prices.
The first two hundred-seventy-five-page mass market paperback I bought way back in 1973 was $0.95. That book today, if it were still in print, would cost me $7.99. Ironically, the writer's relative share of a trad paperback has gone shrunk over the last nearly fifty years. But that is a conversation for another time.
Today, story telling isn't limited by physical resources. A 100K-word e-book takes up 850 kilobytes. By comparison, the digital copy of Star Trek (2009) on my laptop is 1.24G.
The times when readers complain a story isn't long enough are when they feel you haven't told a complete story. It's not that it's really too short. It means either you've missed story beats along the way, you left out the emotional transition, or you left plot threads dangling.
Don't get me wrong. You can leave a thread or two for the next book in the series, but you can't leave too many without making the story feel incomplete.
As I've said before, you got to have a beginning, a middle , and an end. Samwise Gangee can't simply go from the Shire to Mount Doom because his best friend has a problem. The relationships he makes, the changes he goes through on the journey, and finding his inner strength are essential for his happiness at the end of The Lord of the Rings.
What? You thought Frodo was the hero? Nope. It's not just about the One Ring. Sam is the one who saves Frodo's soul. Without both victories, the story would be incomplete. In other words, Tolkien's readers would say that huge-ass epic was too short.
Readers feel the truth even if they can't put a name to it.
So make your story true regardless of how many words you use. The readers will love you for it.
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