When I get down to 30ml. I would have already have panicked and have ordered probably 120-200ml. Really. I've built up quite a supple of diy juice etc.
But I would panic if I got down to one battery working. Again then I would (if I could afford it or hock something) order 3 replacements.
I'm even thinking of putting one in with my emergency batteries/flashlights/etc. Snicker In case of a disaster. So unless we get something like a N.E.M.P. I would be set. If there was an N.E.M.P vaping would be the least of my concerns. LOL
Nuclear Electro-Magnetic Pulse. LOL
Prompted by the memory of a guy that called into a radio talk show wanting to know how to protect his VHS tapes in the event of a Nuclear War. Really happened. LOL I'm not quite that bad. YET LOL