I don't upgrade my phone because it still results in me spending money. so you aren't "saving" anything. thinking you are "wasting money" by not using the upgrade subsidy is confused logic. If you are spending money, you are not saving money.
I have no interest in upgrading my phone just to sell my old one on Craigslist.
You missed my post about how I come out in the black with my phones, and that is from buying them off-contract. Sell the iPhone 5 for $550, buy the next one for $650. In the meantime, I've earned over $100 from the iPhone just from iOS rewards programs.
I meant to sell the new one on Craigslist if you aren't going to use it. You pay $200 for a $650 device, and sell it on Craigslist for $650 to recoup the $450 subsidy.