When shopping for a king-size down comforter, it is essential to consider several key factors to ensure you select the perfect option for your needs. First, pay attention to the fill power, which indicates the quality and loft of the down; a higher fill power (600 and above) typically signifies superior insulation and warmth without excessive weight. Additionally, examine the shell material; a high-thread-count cotton or cotton blend not only enhances durability but also provides a soft, breathable surface for comfort.