1. Temperature ratings are usually 10 or 15 degrees lower than they should be.

  2. Down is lighter and less bulky than synthetic filling, but you’re screwed if it gets wet.

  3. Make sure the zipper is on your preferred side of the bag.

  4. Everyone looks at length, but shoulder girth is important, too.

  5. Don’t buy a bag without a durable water repellent (DWR) finish.