Batteries have a logarithmic degradation of capacity, meaning using the quick charge function will cause the capacity to drop about 10-15% really quickly, likely within the first year. So dumping the phone in 3 years is likely right when you hit the shallow part of the curve and the battery stops degrading much.

This. I still keep my old 500mA phone chargers and use them on my phones to be gentle on the battery for slow, overnight charges. I am also a battery expert in my day job…