There are two basic schools of writing: Pantzing and Plotting.
Most of the writers I've talked to have been pantzers, meaning they write from the seat of their pants. They have no idea where the story is going until they have written it. At best, they have a few general moments they know they want to work towards, often they know how they want begin and end the story, but little more than that.
Pantzer's don't know who is going to live or die in their story at the beginning, or even who the central characters are, until the words are on the page. They don't know who will live and who will die. They often don't know who the heroes or villains are, or what they are fighting over, or why they care. Pantzers write sentence after sentence to discover the story they want to tell, then edit what they wrote so it reads well.
This, to me, is a bizarre way to write.
I am a plotter. That is, I need an outline before I can write. I need to know who the central characters are, what their goals are, what they will do to achieve those goals, and what they won't do. I need to know who lives and who dies, how they die, and who would be better off dead. I need to know what the conflict is over, how the characters break down into sides over the conflict, why it is important for each side to win, and what the result of any particular side's victory means to them and others. I need all of this and much more information; not in a vaguely defined way, but hard specifics I can write towards.
Pantzers have the advantage of speed. A pantzer can crank out a good size story in a year or two. I spent decades fleshing out the story for my epic, Gods Among Men, before I felt like I could really write much of it. I wrote a lot in those decades, but whenever I ran into a question I didn't already know the answer too I had to stop and spend days, weeks, and even months finding answers that satisfied me and worked with my central plot.
I think the result is worth the extra time it took. I can give detailed answers to almost any question about the world or the characters or the plot. More importantly; I like, really like, my plot, my characters, the story arc, the settings, and so on. I love the world I have created in my mind, with all of its flaws and including the parts of it that run against my personal ideology.
Currently, I am editing At The Lady's Behest Comes..., the first book in Gods Among Men. I hope to have it up to submission quality by late this year, though I fear that is optimistic. Looking forward, I believe I can create first drafts for the remainder of the story as fast as any pantzer could, maybe faster. Editing each book to make them publishable will take longer, of course, but I know where I am going and I have an outline to get there. That's a nice place for a plotter to be.