Some people freeze it, some keep it in the fridge, some just keep it cool and dark. The only safe method at this point in time seems to be the last.
Some say freezing is OK but there are liquid suppliers who disagree. You'd have to do a two-year test with several types of liquid and be able to analyse the nicotine content at the end, to know for sure if that works OK - assuming the flavors survive.
Some keep it in the fridge. However one of the guys here apparently lost $200 worth of eliquid doing that. I believe he is a zero-nic vaper so the problem must have been flavor loss or contamination. If you've ever stored a light-flavored food in the fridge and had it ruined, you'd know why this happens - water vapor and flavors somehow cross the storage container barrier and either get out or get in. Maybe if the liquid is stored with zero headspace in glass bottles and then wrapped in a sealer on top of that, you'd be OK. Maybe - because water vapor plus the flavors it carries can cross just about any barrier by osmosis.
If you store eliquid in dark glass bottles, with no gap above it in the bottle, in a box so it's totally dark, in a cool place with low humidity, then that is proven effective for the life of the liquid which is stated as two years. If you don't have anywhere like that to store it then you would have to be creative. Just now, it seems that no one has come up with a proven safe alternative. I haven't heard of anyone who states they successfully froze or fridge-stored their supplies for two years, and that's the number you have to beat.
If you are looking to stock up for the long term I think the best policy might be to get very high strength base liquid (eg 100mg) and seal that to the
nth degree, then store it cool, dark, and low-humidity. All the other ingredients of eliquid are over the counter materials and can't be restricted never mind banned. Bear in mind that high-strength nic liquid is dangerous and you shouldn't be going anywhere near it unless you have some appreciation of the issues.
The only other vital part is the atomizer and again there are arguments about how to store those. All I know is that you need to test them before you store them, as some are likely to be dud. 50% of the last batch of 510 LR atties I bought were dud or faulty.
There aren't many people who could give you reliable advice on this subject and one of them is Nick O'Teen, the pro eliquid manufacturer. So go ask him
He created the most expensive eliquid ever made, Caviar Flavour, and he knows a thing or two about it. He has the Decadent Vapours supplier forum here. He only wholesales to other suppliers, and the liquids you buy often come from him.
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One thing this has taught me is there is nothing they arent capable of when it comes to mugging there people with a smile on there face. Anyway great posts you guys and gals kicka>> 
