How long have you kept a phone previously? Most don't last more than a year or two before replacing it. As for 2015, Sprint has the option to renew, and that is when the contract runs out with Clearwire, not when it will be turned off. Besides, 4g is not the primary network, 3g still is. 4G is only a bonus if you happen to be able to get it, and even then, most Sprint users left it turned off unless they needed it because of battery life. It's not going to replace 3g as the primary data system for at least 2 more years as the network needs to be built out more and the radios need to become more efficient. Battery life is why the Iphone 4S didn't come with 4g.