I got 7 1/2 years out of my old IPhone 3gs. When I finally went for a new phone, the sales staff at the store was amazed it lasted as long as it did.
One of my sisters really liked her (non-Apple) phone, didn’t want to change phones, it worked great, and (like her brother) she regards a mobile phone as a communication device rather than an alternative lifestyle. :^) She finally had to say goodbye at one of their contract renewals because the model wasn’t supported any longer.