This is pretty similar to the "pantsers vs plotters" debate in creative writing. Do you need an outline before writing a novel? How much of one?
you also need a well-thought out outline for any larger work like a novel, or, it will be a disaster, or at least not be anywhere as good as it could have been
credentials: creative writing for decades and experienced 1sthand tradeoffs of each. my verdict? seek the Hegelian dialectic. ;-)
related semi-tangent: with fiction I also adopted the rule to write the Ending first. because, for me at least, it then crystallizes what sorts of Middles and Beginnings might lead to it, and make the most sense or have the biggest emotional impact on the reader. which then practically paints out the character journeys for you, as the author. very helpful tactic
It's more common than you think.
Hasn't been the case for me so far. Every story and essay I've written started with an idea. If there is an outline, it gets thrown away page 2 and never returns. On my second novel and this still hasn't changed.
My writing is actually better this way because I start with characters and plot emerges as they deal with the forces around them. I never know how they will react until they do.
I program the same way. Write a bit, revise, write a bit, revise. Drives some people nuts if they see the process, but the end result has been just as good or better than my coworkers throughout my career. (I'm a huge fan of tests. My revise step includes adding tests.)