When you ask the question, "how to choose a sleeping bag", the first thing most experts will tell you is to pick for a specific trip the correct temperature rating, which is the lowest temperature at which a bag is intended to keep the average sleeper warm with the assumption that he or she is wearing long underwear and have a sleeping pad underneath. You can't use your winter sleeping bag in the summer and vice versa, unless it's the Kammock Thylacine modular sleeping bag. You can customize the Thylacine sleeping bag to the level of comfort and warmth you need for your trip by adding or removing the baffles (synthetic or down). You can also adjust the length and width of the Thylacine to avoid dead space especially in cold weather; you can resize the footbed and make five body adjustments to get the right fit at the chest, hips, thighs, knees, and ankles. The Thylacine is a Kickstarter project that will only be funded if at least $60,000 is pledged by Tuesday Feb 4, 10:00am EST so if you love the idea, head over to Kickstarter and show your support.