Upgrade? Again? I'm old enough to remember when you bought a 'camera', a box to which you fitted a lens and into which you placed 'film'. Colour, mono, fast-film, slow-film etc. Your camera would last for years, only the media needed changing. Now in the 'digital age' Nikon, and indeed all the camera manufacturers, have to come-up with something new annually to keep production rolling. So next year expect a D7200 or maybe a D8100 with a 36Mb sensor so all you D7100 owners believe that you now own a dinosaur, and can't take a decent photograph without buying the new one. It's called 'Marketing', and you are the 'Consumer'.