>>802099>>802069>>801965It really depends on your gear. Folks with very high quality tents, rain gear, and sleeping gear miiiight be able to do a 40L for extended trips, but it would still be pushing it. If you have an older model large tent, or a bulky synthetic sleeping bag, or rain gear that doesn't roll up well, then forget about it. (I'm aware you can stash some of that outside the pack)
It also depends on what kind of food you're bringing. If you can afford to buy all dehydrated/freeze dried meals in pouches, then 1-2 weeks worth of food is doable as it is so light. But if you are like me and pack rice, sardines, GORP, stuff from the international food isle at the super market, then 1-2 weeks worth of food is going to weight a lot more.
Honestly I use a 70L for all my trips. I always have, I probably always will. I have extra space for shorter trips, and sometimes that allows me to bring some fun stuff I wouldn't normally like a bag of popcorn, a kite, whatever I feel like.
Also I just don't want to buy a smaller bag if I have something that works already. Although they do look nice.
