Pg is pretty good at preventing bacterial and viral infection when airborne, I have no reason to believe it wouldn't preserve the nicotine. I always order at least partial PG, both for that reason and for increased TH.
Furthermore, the shelf life of medicines and chemicals tends to be quite a bit longer than labeled. I've personally taken loritab that was 8 years out of date with no ill effects. (worked just as well as when it was new, back pain bye bye) Please note that I'm not a medical professional and do not take my word for it.... But yah...somehow I doubt nicotine would lose its potency if stored properly in a reasonably thick, dark glass container.
Furthermore, the shelf life of medicines and chemicals tends to be quite a bit longer than labeled. I've personally taken loritab that was 8 years out of date with no ill effects. (worked just as well as when it was new, back pain bye bye) Please note that I'm not a medical professional and do not take my word for it.... But yah...somehow I doubt nicotine would lose its potency if stored properly in a reasonably thick, dark glass container.