Some writers are organised. They create an outline and write their novel from that. While the story may deviate a little it is basically in place before they start.
Others just start writing, and end up with this big, overblown mess that’s full of holes. They have to chop and tweak and move things around and add extra bits.
We’re one of the messy ones.
As a result, we probably write three times as much as we need to (not all in the same draft). Our working out is done on the pages of the novel, rather than beforehand. What goes into the first draft may not remain in later drafts.
Even so, a lot of what you cut is not wasted. It ends up as back story. You know your characters and your worlds so much better because of this back story.
Occasionally that information even comes in useful in unexpected ways in later drafts.
In draft 1 of Barrain we had a sub-plot where Scott was fed a drug called casseye. It was odorless and tasteless. Barrainers fed it to their slaves to make them docile.
We got rid of the sub-plot in the second draft, and we got rid of the slaves. Neither were necessary to the story.
Then here we are in draft three, trying to work out how Caid and his group could possibly have committed the massacre that starts the story. And suddenly we have it.
Casseye. Of course.
So if you’re messy writers like us, don’t despair over those big chunks you have to cut. They’re still useful. And who knows, they may even come back into the story in a different guise in a later draft.