Posted 07 March 2017 - 10:35 PM
Are you asking how long a cell will last in general (whether it can still function as a phone or not) or how long it will last as a phone? Those are likely two very different answers.
For the latter, you cannot just assume away the time frame of when cell companies might no longer support a particular phone or technologies that a particular phone uses. For example, as I noted in your other thread where essentially asked the same question, AT&T just dropped support for 2G, thus killing the original iPhone's ability to work as a phone on AT&T's network. Of course, an original iPhone could still be used for other things (such as playing music). So, in this specific case, if you are asking how long it would last as a functioning phone, for the original iPhone, it lasted about 10 years. If asking how long it would last in general, then it can still be going strong even if you cannot use it as a phone. Now, I do agree that 4G (i.e. LTE) is not likely going anywhere soon, but 3G is a tougher call (no pun intended). It is not beyond the realm of possibility that 3G could start to go away from some carriers in the relative near future (say 4 or 5 years or maybe less). It will likely not be really threatened until so-called 5G (or whatever comes next) is actually widely implemented. And even then, it is possible that 3G tech sticks around for calls, while 4G or 5G handles data (I believe many carriers still use 3G tech for calls now).