I tend to keep my cameras for quite awhile because I like to think I have chosen the cameras that do what I want/need it to do well.
My DLSR life has gone from Nikon D70 > D200 > D300 (replaced a lot earlier than expected because it, and everything else, was taken in a burglary
) > D300S > D500. Each camera bar the enforced D300 > D300S change was for comparatively big changes in performance in a lot of areas. Technology was moving a quite quickly in a lot of areas for a number of years. For sensor performance especially though, we seemed to have plateaued for awhile.
The new Pentax K-3 Mark III has recently come to bettering the the D500 in some areas, but enough to change! Nah, not for me. The D500 does everything I want/need it to do thankfully.
The reason I went with Nikon for the DSLR rather than the slightly better specced Canon was because my knuckles scraped the lens on the 350D/400D of the time, and the D70 felt it was designed for my hand, and each camera I got seemed to get better in that respect, peaking with the D300S. So ergonomics have always been important for me, and while the cameras seem to get heavier as I get older,
the size is the size of camera that suits me.
I've always felt that the APS-C / DX format is the right format for me as the best combination for cost, size, weight of cameras and lenses, with the added the field of view / focal length options a crop sensor gives imho. If I were to think of a replacement that rules out a lot of DSLR's and most mirrorless cameras as options.
I prefer the optical viewfinders too, which again rules out mirrorless cameras, for me. Mirrorless cameras have nothing that attracts me bar interest in the technology, and I can have an interest without the need to own one.
If I were to lose everything for any reason, like I have done in the past,
I would strive to get the best version of what I had before, like I did in the past, so upgrades if available, but if the upgrades are not there, as it would likely be now, (I can't see Nikon replacing the D500, though they surprised me and many others with the D500
) then I would get exactly what I have now. If / when my D500 wears out, I will get the best D500 I can find to replace it.
It is great not to have the GAS any more.