I'd say it depends on your gear and conditions. I'm fine going out for a few miles on relatively well traveled trails in the summer time with just a small lumbar pack and a water bottle. For a few miles in the spring or fall I'll probably want the space to stow another layer of clothing, so I may move up to a day pack without any kind of hip belt or frame. Heading out to a more remote location for a longer hike, I'll probably take my L.L. Bean pack. . . I think it's an older version of the Bigelow mentioned by Rich_S in your other thread. . . I'll probably be carrying lunch and maybe full rain gear instead of just a poncho, and maybe a hammock and a light tarp if I want to do some lounging around for a while. I also use the L.L. bean bag for light overnight backpacking trips. For more "luxurious" trips or at colder times of the year, I'll carry my Kelty external frame and include a stove and extra bedding and maybe another tarp, and binoculars and maybe a book to read and. . . well, you get the idea. . . an external frame pack can hold a ridiculous amount of gear when you start lashing extra stuff to the frame. I haven't done any trips longer than one night so far, but I could pull off 2 or 3 nights with the L.L. Bean pack, maybe more if I was careful about how I packed and if I took mostly dehydrated meals, and I'd guess up to a week or more with the Kelty. I just need to get the time off work to try a longer trip and see if my body is up to what I think my packs and other gear are up to.
