Look, Apple release products on an annual basis. It's not worth it to get a new device every year, especially when the differences are as incremental as they are. Either every two years or maybe even three years seem to be good times to upgrade. I'd even say wait until they are close to announcing a new product, and drop the price on the previous model. I got a good deal on an iPhone 5 right before the 5S was released, and I've not once thought I should've waited and paid more for the 5S instead. I might get a 6 this summer though.