Mobile Phone! How often do you change your mobile phone?

The first phone I got was a very old phone previously used by my father but I lost the phone within 3 or 4 months due to carelessness. After that, he gave me his phone which was an Acer phone (surprise surprise, it is an Acer). It became faulty not long after that so I changed to Samsung phone which was also previously used by my father. My first phone, owned by myself, is a Nokia 3650. It lasted for a couple of years before changing to Nokia N70 which has cost me a bomb. I bought that phone about 2 or 3 years ago and have been using it until now. I have no plan to change a new phone even though phones such as IPhone, N82, P1i are looking pretty good and useful. But I do realize that most of the time, I will only use the most basic of functions in the phone. No point for me to spend so much since phones are liabilities and their values depreciate very fast with time. Might as well spend the money on something more useful and applicable.