I bought the Air about 6 months ago and can't see myself needing to update anytime soon. I update my iPhone as soon as the new ones come out, but my iPad does a great job until they release one with huge updates.
I am hoping we get an Air 3 this year. I am very happy with my original Air, it is a fabulous device. However, I would like more storage and an LTE modem. Shared data was still pretty expensive when I bought my Air, so I don't regret the purchase but I definitely wish I had that option now.