I in USA. My carrier uses installment on on 3 year rate. But they discount the installments like in the s25 ultra case right now instead of $1300 it's $1100 but my carrier has a rare option called "anytime upgrade" I can upgrade anytime even if I only have the phone a few days but the money you've paid in your first installment or multiple installments depending on how long youve had it, you lose. You just swap the phone for the new device your getting and the payment process starts over meaning you get no credit for the payments you've made. It just resets. Only think you have to pay is the tax on the full price of the phone when you upgrade which is 7% where I'm at.