I'll follow Jim's lead...
With the length and breadth of what Butcher is doing with so many books planned, you have to follow an outline or you can end up somewhere you didn't want to you. I think he said something like, "I have my outline and I'm sticking to it." I think the unimplied followup sentence was...."and it's for me to know, you to guess and then read and find out.."
I love Jim's work, and I'd not read that but it fits with how the series feels to me.
I'd put up as a counterexample, again, Steven Brust's Vlad Taltos series. Projected as nineteen books, of which ten are in print and the eleventh has been handed in: I am absolutely sure it's not going where he expected it to, both from things he says about how he writes and from there being a short story set well in advance of the earlier books which is no longer "canon" because the novels getting to that point changed in the writing. The same is true of P.C. Hodgell's Kencyrath books. Both these series remain excellent.
Recently I've learned to take the characters where I want them to go and get where I want to OR I can let a character take me along (a short path, probably cut out later), but like spoiled children too much leash will spoil the child (and the story).
This all depends on how you interact with your characters.
Myself, when I have a key role to fill in a story, the first thing that character will start to grow from is "needs to have X reaction to situation Y and W reaction to situation Z". If I give them their head, I alreayd know what they are going to do about that particular set of important stuff; what they do about thinga along the way has to be fresh and new to me, though, or the book turns to cold porridge and I can't actually write it, and that usually gives me things I didn;t know which complicate and enhance the bits I know I want to get to.
I have written one whole novel with a protagonist who spent the entire story wanting the plot to leave him alone and the competent authorities to take care of it so he could go out and have a couple of nice meals and meet someone cute. He got poked a bit to get things going, but not much more so than many other stories; it did not take the imminence of a Dark Lord threatening the world or the discovery of a bloody murder, put it that way.
Every word, every sentence must put the reader further into the action/plot of the story. Think of it as a screenplay--the side passage can be brought in as a single sentence or a careful selection of a shadowed adjective here or there. Much more interesting than a three chapter side passage meanderng around.
I adhere to some combination of Brust's Cool Theory of Literature and C.J, Cherryh's dictum about every scene needing to do at least two things, and most needing to do three. Those three can include world-building, plot, character development, and so on, any of which are useful. I think if you're writing a novel, scene-by-scene and para-by-para is enough on which to scale this; word-by-word is a poetry level of density, not a prose one, and very few people can keep that up at novel-length; and those who do tend to produce novels as accessible as
Ulysses or Thomas Pynchon.
