When the temperature drops, it's all about staying warm and cozy — especially when you sleep. Instead of cranking up the thermostat, use a down comforter to keep you toasty throughout the night. Whether it's real down or the alternative version, you'll want to make sure you're picking one that will offer the warmth you need and will last for years. Here are a few buying tips you should consider.

1. Know the best time to buy.