Four layers for the year. An overshirt, a trench, a wool coat, a quilted vest. Nothing that goes out of style by March.
We made four coats. We resisted the urge to make a fifth. A wardrobe doesn't need more outerwear than this; it needs the four pieces to actually work, which means construction that holds up to weather, weight that's correct for the season, and a shoulder slope that lets you layer a sweater underneath without bunching.