Bill,
Speaking of aging, how long are your extracts (bases) lasting before they loose their tooth?
Well, my home-brewed extracts are still fairly young. My first was done in the spring of 2013, the next nine over the summer, and the most recent four in the fall. Average age is about six months. As far as I can tell, they're at least as good now and perhaps better than they were when freshly extracted. I'd guess that they're in the prime of their lives and should remain so for a good while to come, perhaps another year.
I've had some retail juices that went seriously downhill after six months to a year, yet other retail juices in my stash are now three years old and still hanging in there nicely. The oldest juice I have is a bottle of Janty RY4 from 2008 (thanks to
KentC's generosity), and that juice seems alive and well to me, although I don't know how it tasted when fresh, since I was still two years away from vaping back in 2008. Kent tells me that they're about 90% of what they were new---still flavorful, but slightly calmer.
Extracts and flavorings are a bit harder for me to track with regard to their lifespans and flavor loss, but apparently it's very much a case-by-case kind of thing with few hard-and-fast rules. If my home-brewed extracts have an 18-month lifespan, that won't be too shabby, especially given how inexpensive they are to produce. So far, it looks like they'll make that without even breathing hard.