Well, we are actually going to be leaving Sprint (our carrier) when we get our tax refund. So, the hope is that I can find T-Mobile iPhone 5s (plural, not the 's' model) on eBay. I'll dream and say I hope they come with iOS 6.
So, there's that. The old iPhones will be retired as media devices/game machines for the kids. If someone needs a Sprint iPhone 5 at some point I will probably pass it along. We don't sell our old phones and it's very rare for us to have them die on us.
My wife's own iPhone is an original she got in 2013. Manufactured in November 2012 and it's still going without issue. She's still on iOS 6 (lucky her), jailbroken.
We've had a long history of our devices living well past their service. Both of our old phones were sent out to people who needed to keep their Sprint SERO plans (an employee discount plan) and my sister's 3GS is being used right now as a daily driver by one of my friends. I used that phone for a year or so on WiFi with Google Voice/SMS and iMessage. Pretty good condition when I passed it along.
As to change…well, actually I am like you in one sense. I work in the Graphic Design field. Both Adobe and Quark force me to be current all the time. If you do not adapt in this field you will fail. Change is the only constant.
That said, personally, I do not care for change, except in narrow instances in the tech field. But my chosen profession requires me to adapt. But for my own personal self I can choose what I wish to use. An email sent from a 3GS or a 5 is the same as an email sent from a 6+. So, I stay with what I like. Especially since my wife and I usually only upgrade every 2 to 2.5 years. I want to like a phone that I am going to use for that length of time.