If your buying a 1 year old phone by the time you own it it's a 3 year old model. No wonder you give them away would be worth 1/4 of new price or less.I tend to gift mine away so not bothered about cost retention. The phone is paid for and written off once the contract ends.
My scenario doesn't work for you. Your way you are paying near full price for a 1 year old phone for another 2 years, doesn't make sense to me, then rinse and repeat, talk about being behind the 8 ball.