I feel sorry for Nikon owners.
It doesn't matter what model they buy, even when first released, as a few months down the track, Nikon will bring out a new and improved version of it making your current model obsolete and now worth substantially less than it cost you. Remember the D600 then the 610?
Canon does hang onto models much longer, and hence they have better re-sale value later on as say, after 3 years, your Canon may be just superseded, but if you had an equivalent Nikon, it would be 3 models old and practically worthless.
I'm not saying that Nikon cameras are no good, in fact, they are very good indeed, but constant model updates is not how you keep up the perceived and resale value of products.
It also makes it more difficult regarding spare parts too, as many models mean lots of parts and distributors only have so much space and money for parts.
I feel sorry for people who buy cameras based on how much they can sell them for.
If your camera is in good enough condition to be sold as "mint" or "near mint" condition then you obviously haven't used it very much.
While I can understand this for lenses....for camera bodies, they are a depreciating asset. Every camera body I have bought has dropped in resale value over the three years I have owned them. The lenses i have bought have generally been worth more over time due to inflation and increasing prices year on year. My 16-35IIL cost me £850 new, it's still worth close to that S/H and new they are nearly £1200. My 85 f1.2 II L cost me £1200, it's worth nearly that S/H and it's new price is between £1500 and £1800 depending where you buy it.
Camera bodies are electronic devices like your iPad, iPhone, iMac and depreciate accordingly as their function degrades.
I sometimes wonder if the people that care most about the resale value are those that are always running with a month to month non-$0 debt on their credit card and thus see the resale value as being a way to gain back that lost debt, so to speak.
Some of us (me included) always sell the old camera to fund the new camera, so that we don't need to pay the full price for it when we upgrade our camera. In the idea scenario, when a new model come out, we should have save enough $$ to pay for the difference after we sell the old model.
If the new camera "refresh" too fast, we might not save enough $$ to perform the "sell old, buy new" upgrade especially for a mid range full frame DSLR like D800 which is not cheap, so we wait... By the time, we ready to perform the upgrade, a new model launched (may be D900) and the value of our old camera drop even further...
Hmm... may be this is the reason why Nikon don't sell as many camera as Canon as their model "refresh" too fast which make the resale value of their camera drop so fast that it's make no sense to perform upgrade, so Nikon user will just use the camera longer until they save enough $$ to buy a new one at full price.
Have a nice day.