There is lots of reasons to upgrade.
Here is a comparison:
http://snapsort.com/compare/Nikon-D7200-vs-Nikon_D40X
(TL;DR at bottom for anyone that doesnt want to read all this)
Hey guys, amatuer photographer here like the most of us, this is my biggest hobby/pursuit and my best link to the art world which is something I greatly admire. I'm currently, and have been for 3 years or so which is when I got into photography using a Nikon d40 with it's 18-55mm kit lens and a Nikon VR 55-200mm lens as well as a much older Nikkor macro lens every once in awhile. I've gotten very used to this camera and I can say the 8mp has never held me back and theres a lot to love about it, I'd still recommend it to people. I'm very proud of some of the pictures I've taken on it but at the same time the better I get and the more knowledgeable I am about photography the more I notice I'm missing. I'd also like to step up from an entry level newbie camera to a prosumer camera which is what I consider myself. Reviewing the two side by side reveals a lot of on paper improvements and likens the D7200 to a Canon 70D which my friend owns and when I've used it I enjoyed immensely the experience and the pictures. I've definitely gotten over the specs make a better picture mindset but I am of the mind that newer features and better specs allow for more options than I have at the moment. My father is of the mind that none of that matters and because people were using this camera (D40) happily in the early 2000's I can use it happily today. While this is partially true, it still takes good pictures, I have the option to take better pictures. And yes the paintbrush doesnt make the painter but a better brush means a better product.
my birthday is coming up soon and Im looking to get a new camera, I'd like to ask for my parents to shoulder half (or less) of the price as my only present, I have lenses that work with the D7200 already that get the job done which makes the body only very affordable for a camera in it's class. I may even go and buy it myself a couple months later by just skimming some money off my paychecks for awhile if none of you nor I can convince my Dad of the merits of the D7200.
TL;DR
So the point of this lengthy post is to hear testimonials from both sides, pro and con upgrading from people who have personal experience traveling from similar cameras (D40->D7200) or more extensive knowledge in general, all opinions are welcome! Thanks all of you!

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