I guess it depends on your gardening approach and what you have in it, as well as what pest problems you experience.
I currently have raised beds, so my fall work is ensuring all the dead plant material is cleared off and put on the compost pile. Other than the asparagus bed, I work up the soil to try to break up the clay. In Spring, it's a quick "fluff up" of the soil, and I am ready to go.
When I had the more traditional garden (and had chickens), so in the fall, I would again clear off the garden, turn the chickens loose on for a week or two, and then till in organic matter (leaves, grass clippings). Over the winter, I would spread the coop litter over it. In the Spring, would till everything up, let the chickens on it for a week or so, then start the planting season.
For me, the objective is to remove anything that fostered weed or pest growth, and build up nutrients in the soil