It really wasn't a switch, it was more like getting a second body as a backup. I thought I had something wrong with my D7100 when I was on my Denali Road Lottery trip. Turns out, the diopter adjustment for the view finder was turned while taking in and out of the bag. But that trip got me thinking that maybe with the expense and the, "Once in a lifetime" trips I've been talking up here that having a 2nd body as backup is probably a pretty good idea.

That trip brought up another argument for a second body as well. For wildlife shots I was wanting my 200-500mm zoom which is a beast of a lens, for landscape I was wanting my 18-140mm zoom. It always seemed like I had the wrong lens mounted for what I needed at the time. The thinking was just mount the 200-500 on a body and the walk around zoom on the other. The last cruise I did of Kenai Fjords I was able to use both bodies leaving the 200-500 fixed to one body. That made things a lot easier.

Originally I had intended to do it on the cheap and get a D3500 or D5300 body. The staff at the local camera shop talked me out of that idea. The reasoning is the D7500 and D7100 have the same control layout. I had thought about going with an FX body, but that is a lot more expensive. So it really isn't a switch, more like an expansion of what I already have and the ability to use the DX lenses that I already have.

I agree with your choice of a second body.
Way back when I was doing a lot of traveling and was an avid photographer, I always had two bodies with me. Sometimes it was for different types of film, more often to have two different lenses readily available, and always for backup redundancy.

For my recent trip to Kenya, I rented a second D7100 (I own one) so that I could leave my 18-200VR2 zoom on my D7100 and put my 200-500VR2 zoom on the rental. Many folk had advised not doing any lens changes in the field there, and my solution was to have 2 cameras. It worked very well--I kept my own D7100 on its strap around my neck for quick access (shots through the window while moving) and the rental was in my camera bag. In the vehicle on game drives I took the rental with big lens out and made it available for use. We had adequate time at each stop for me to use both cameras.

Years ago, when I was still using film, I carried 2 cameras: a Nikon FE with ASA 800 film and a 28mm f/1.8 lens (for inside work) and a Nikon N70 with ASA 400 film and a 28-200 zoom for everything else. The FE was on a short strap and rode high on my chest; the N70 hung down around my belly button. It was awkward, but it worked.

flashguy