A long coat should sit comfortably over knitwear or a blazer without pulling across the shoulders or closing strain at the buttons. The shoulder seam should align with or slightly drop from your natural shoulder, depending on whether you prefer a sharp or relaxed line. Sleeves typically hit at the wrist bone, and the hem usually falls below the knee for full coverage. Check size notes and product measurements to decide whether to stay true to size or choose an intentionally oversized cut.