Ditto. Redundancy is key. That's one of the reasons I love my eGO setup - it's versatile, reliable so far, and cheap enough to have multiples (I have 4 - 2 1100mah, 2 VV). One generally lasts me most of a day, if not all, but I always carry a fully charged extra with me. THAT gives me the comfort I need that what I desire will be there when I want it.
vape on!