Longest owned? Hm...
A Rolleiflex 3.5E2 I bought new in 1966. Used a lot until about ten years ago. Serviced for the first and only time in 2001. Taken out and tested (winding, speeds checked etc etc) This thread is a kick in the pants for me, and I'll be taking it out in the very near future for a shoot.
Next, a pair of Nikkormat ELs I bought in the late 70s. Still working a new. I take them out of mothballs 1-2 times every year and shoot a roll of B&W film in each, to remind them that they are still loved. Alas, I've not processed any of these films since 2012. So!
Two Rolleiflex Ts I bought in the 1990s, equipped with 16 exposure kits, for use in my travels at the time. Very little used. Taken out and played with like the Nikkormats.
All this reminded me that it's time for me to get more into film again while I can, before it (and I) disappear from this avatar...
Digital, not so long ago. Two D700s, one bought (new) in 2012, another (used) in 2017. Both malfunctioning (gross overexposure) and unreliable. A Nikon Df (a gift to me in 2018). I bought a Nikon Z6 this year but had to return it three times to Nikon for servicing and the camera shop owner finally gave up and I was refunded.
I now wonder why I didn't keep the Nikon D90 I bought new in 2009 and sold last year to a friend who still uses it and produces superb imagery with it. Built to last. Which would make it 11 years old and still in use. The very best of the Nikon DX prosumers, I reckon.
We won't be writing any future posts like these about most digital cameras. They are, purely and simply, consumer products. You buy them, you use them for a while, they malfunction or die outright, you pitch them into the nearest trash can and you start the process again. Tools. Nothing much else.
So I've decided. No more digital Nikons for me. Life's too short and my aggravation levels over new camera gear sold for top dollar but defective, have risen to way above stratospheric cloud levels. Film is the way. While it lasts...