Layering in writing

I’m returning to an old theme for this blog - layering.
Layering is directly related to the way we work and very often happens when you go back over something you have written
For me, it comes as I write and the plot evolves. Suddenly something becomes important that was not important before or maybe was not there before so I add in layers.
Like me, you may want to go back to a scene you wrote and inject it with an emotion or add in extra information about a character. Was it too bland as it was, was the reader likely to be bored? Or confused?
All this layering is crucial and, for me, it can change stories for the better.
John Dean