How often should you upgrade your Smartphone?

Like how people have preferences about the music and food they eat, there will be a preferred smart device for you—iOS or Android for starters, then which brand, which model, what features, and more. Now, while manufacturers would love to rush out to the stores each time a new model is announced, it is simply not financially feasible or logical for us to buy a new smartphone every year. Phones are powerful enough that the average user won’t notice the difference between the newest, shiniest model compared to last years. Other factors such as e-waste and pollution, the constant price increases for new phones (looking at you, Apple), and many other reasons are actually causing people to hold off on upgrading as it is simply not required. So when should you upgrade? It honestly depends entirely on you. How often do you use your phone? What do you use it for? Are you a power user who relies on their phone for their business?