If need be every 3 to 4yrs,had my present one for a year now so unless it should die on me I shall keep it for 5yrs or so,I got m8s who change there phones like there clothing,don't see the point myself !
Gsmarena is not a good place to make such poll, because 99% of readers are obssessed with mobile phones. Imagine there are another kind of people with totally another personal hobby. There are doctors, engineers, lawyers, workers wich change their mobile at 2-3 years. And mist of the people are poor.