Many writers prefer an outline to be a casual construction, but sometimes writing needs a more extensive master plan. Assignments that ask for an annotated outline help us learn to read deeply. As a side benefit, analyzing a published writer can teach us how to construct a more thorough planning outline for our own writing.
The next-door neighbor just painted her living room. She says she used two coats of color for coverage, bought four gallons of paint, and had plenty left for touch-ups. Her room is a little smaller, so maybe four cans won’t be enough. Then again, she doesn’t have half a wall of shelves, so maybe four cans is still a good guess.
Composition textbooks recommend making an outline before drafting an essay. I won’t disagree that outlines can be helpful, but three practical concerns prevent me using an outline every time I write.