The minimal amount of extra weight from the sack can be worth it for the reduction in volume, and the protection against tears. However, a lot of long-distance hikers don’t use a stuff sack–they just stuff the bag in their pack and let it take up empty spaces. The only reason to stuff it in a sack is to keep it contained, for convenience. Compression sacks are a good way to save space but are a little heavier than a regular stuff sack.
Folding and rolling tends to cause repeated stress on the same parts, and can cause lumps in the stuffing or tears in the fabric. Folding also takes longer and makes it harder to compress.
Bags can get wet not only from rain, but setting your backpack on the wet ground (since you often strap it to the bottom of your bag), or when crossing streams. If you don’t have a trash compactor bag, line the inside of the stuff sack with a regular garbage bag before you stuff the bag in. Fold the top of the garbage or trash compactor bag over so that it is sealed and water won’t get in. If you’re using a garbage bag inside the stuff sack, twist the excess ends of the garbage bag and stick the twist under the edge of the drawstring so nothing sticks out. No need to use a twist tie. They are too easy to lose on the trail and add to trash on the trail.
If your pack has two compartments, store it at the bottom of the top compartment. If it is not possible to fit all of your gear inside the pack, and the larger items like tent and/or sleeping bag have to be lashed on outside, strap the sleeping bag to the top of the pack and the tent to the bottom. When you take the pack off at rest stops and set it on the ground, it is preferable to have the tent instead of the sleeping bag in contact with the ground, especially if it’s damp or muddy. If you strap the bag to your backpack, be sure to try and center it on the pack as best as possible and cinch it as tight as you can. Otherwise many people end up having to stop to re-secure their bag because it is falling out.
To roll it as tightly as possible, kneel with your knees on the end of the bag, rolling it against your upper leg.
If you do not have a stuff sack, cinch the rolled up bag tight with a belt, or a string or rope as a last resort. You may need a friend to hold the bag while you tie it.
Down sleeping bags get clumpy in the wash. To make them even and fluffy again, add a tennis ball to the dryer near the end of the cycle. Never wash a sleeping bag in a top-loaded machine. The agitator may tear the fabric.
Some people turn the bag inside-out and hang it so that the inside airs out (that’s often what gets smelly over time).
Place it in an oversize, breathable storage bag made from cotton or nylon. Spread it out under the bed. Hang synthetic (but not down) sleeping bags on a large clothes hanger.
