DVap, a member of this forum who is into testing nic content and such, did an informal test exposing
ejuice to extreme temps and sunlight. He measured the nic content before and after and found only a negligible loss of nic content after this extreme exposure.
If I remember correctly, he advised that it was not necessary to refrigerate
ejuice unless you planned to store it for a long, long time, something like one to two years.
Regardless of the above, I still do keep the majority of my
ejuice refrigerated. In my quest to find flavors that I like (or can even truly taste), I've accumulated quite a large assortment of different flavors from a myriad of vendors. So far menthol is the only flavor that I'm really 'into' so I have all of these flavors that I speculated on sitting around. Some of them, regardless of being sealed in glass or plastic bottles, make my cupboard smell so I keep them in a heavy duty baggie inside the fridge and that seems to keep them from reeking-out the cupboard.
On another (side) note, I'm curious if anyone feels compelled to shake their ejuice up periodically. For some reason, I've got it in my head that perhaps the nicotine or flavorings separate, sort of like paint, if left sitting around. Any insight into that?