My logic regarding upgrading to "S" versions

For the record this is my opinion after purchasing the "solid number" models(5 and then 6 Plus). So I currently have a 6 plus that I purchased used from Swappa in October 2014. I was going to upgrade to the new 7+ but I realized that I will just buy a used 6S+ and wait for 7s+ because when a new form factor is released it takes a significant amount of time before the best cases are available (i.e.; Lifeproof,Mophie etc). I really got tired of just buying whatever was out and waiting as my favorite companies had Coming Soon signs up for many months after a new solid model is released. I just bought the Lifeproof Frē for my 6+ and that just came out recently. So now I'll just get a used 6s+ in September from Swappa for a great price in great condition and shift to "s" model upgrade cycle. Also I pay full price for my devices so that I can keep my Verizon unlimited data plan. Just wanted to share my thoughts folks.