Eliquid does seem to have a fair amount of longevity, and I don't know that I trust use by dates so much. If the juice looks really, really dark, or tastes off, I wouldn't use it, nor if any particulate matter had precipitated into the liquid. Otherwise, well, it depends. If you have eliquids that you don't think you will use for a time, store in a cool dark place. Even a refrigerator might be okay, for longer term storage, although it may cause the liquid to look cloudy or even separated, well, what matters is what it looks like once brought to room temp and shaken. There are times flavor may precipitate out under cold conditions. I keep my flavors in the fridge, but I live in Tucson, which is pretty much the same as living on the surface of the sun. Any "cool" place created is going to be artificial.
But, 2 years is a reasonable time to finish off a bottle of eliquid. If you come across, ever, a bottle you've misplaced and it's aged a great deal, I generally will make that decision based on how the liquid looks, and if it looks okay I will vape it, and if it tastes okay and I like it, I will use it.
However, these are really decisions you need to make for yourself, you are the one who will be vaping it. I tossed some eliquid that was like 7 years old (it looked fine) merely because I was like, "It's 7 years old, it's really not worth my time." Etc.
Anna