Longevity will depend on your vaping style. The MVP2 lasts quite some time but would required charging if you're out camping for 2-3 days. With external batteries you can easily carry more fully charged batteries in a case.....how many will depend on your vaping style and the length of time you plan to be out camping. I personally would take both my MPV2 and my Provari or mechs with extra batteries. Between all of them I'm sure I could make it 3-4 days without worrying about a charge. Of course I have a lot of batteries for backup.