Even we’ll admit it, the wide world of backpacks can get a bit confusing. You just want a nice bag that fits all your gear and doesn't wear you out before you make the peak. But there’s the problem – carrying lots of heavy gear and being comfortable is a contradiction. A bag must be pretty canny to do both well. A 40L backpack sits in the sweet spot between lightweight daysacks and heavy-duty 80L rucksacks. They’re extremely flexible – working for average day hikes and overnight wilderness camping. They also give you the extra room needed for climbing gear or winter hikes.