All depends upon where your hunting. I have to spend an hour climbing the mountains here in Virginia and I sweat heavily. So I dress very light to begin the climb and carry a large pack that includes my coveralls, baselayers, any all the essentials such as gloves, headgear, extra ammo, extra light, knife, calls, binos, a drink or two and of course some toilet paper. When I finally get to my stand I strip off my outer shirt and sweaty tee shirt and cap and stuff them in a plastic bag and then back into the backpack. So where you hunt can play an important part in determining what size pack you need. If you hunt the flatlands of the midwest, you can probably get by with a smaller bag and as some others have mentioned, I wouldn't spend the extra bucks just to get a "top-of-the-line" pack. Most any brand will hold up for a lot of years unless you're unusually rough on them. I picked mine up from Sportsmanguide. Also depends upon how long you will stay in the woods. Frequently, I go in around 5AM and don't come out till dark. If you normally come out at lunch time, you don't need to carry as much stuff as someone who spends 12-13 hrs in the woods.