There's no reason to upgrade a phone more than once in five years at least for me.
I bought a an iPhone 15 Pro Max few months ago and compared it to my S10+ which I bought in 2019 and still have. There's practically no difference for regular day to day stuff, except for the camera advancements which are notable (but not night & day either).
It was only the frustrating battery life, and desire to enter the superior iPhone camera ecosystem that forced me to upgrade.
I bought a an iPhone 15 Pro Max few months ago and compared it to my S10+ which I bought in 2019 and still have. There's practically no difference for regular day to day stuff, except for the camera advancements which are notable (but not night & day either).
It was only the frustrating battery life, and desire to enter the superior iPhone camera ecosystem that forced me to upgrade.