Didn't know that! So, all the iSticks etc. that I have stored will have to be topped up every 6 months ..oh well, suppose I'll just have to do that.You would be better stocking up on mods that take removable batteries, those with the built in Li-ion ones need to be stored with a half full battery, then topped up at least every three-six months, whereas normal 18650 batteries can be bought any time as they are also used in other things [RC Boys toys].
I'm very happy with my Sigelei mini, so may get more of those, and the Kanger is OK too. Wonder if there's any of the cylindrical types (like the iPOW etc.) that have a removable battery. As well as the 10W iStick, I like those for taking out with me.
18650 batteries aren't purely for e-cig mods though are they - or do I need a stash of those too?