About vape liquid storage, nicotine is a highly perishable chemical. It’s just determined to go bad! PG and VG to an extent act as a preservative, but only so much. Sunlight will make it go bad. Heat will make it go bad. Oxygen will make it go bad. It just wants to be bad. So, deprive it of the things that make it go bad.
Your liquid will yellow a bit over time, which is fine and just the result of oxygen. And since we don’t use preservatives or color inhibitors, it’s just going to get a little darker. We suggest only buying what you’ll be using over a short period of time. Keep it out of the sun and away from heat. Simple.
Since everything from our website is mixed when it is ordered, and applying what we've suggested, the combination of everything should insure that you’re using the freshest liquid possible without vaping all those additional chemicals to protect the color and longevity.
However, keep in mind, we want to keep any ingredient chemical laundry list as LOW as possible, so we don't use preservatives. At about the three month mark, when it's dark from exposure to the various aforementioned causes, you should probably consider throwing it out. We DO have an expiration date on the bottle, but that's only when the bottle has been brand new/unopened and stored under optimal conditions.