I just counted and I've been thru probably 10 or 12 cameras over the last 40 years (excluding phone cameras). DISCLAIMER- went probably 15 years without a decent camera in the middle, so I turned over cameras a bit more than that- probably one every-other-year when I'm shooting seriously. Almost without exception, on the day I bought them I either knew or hoped desperately that THIS camera was 'the one'- the perfect camera for me. Sometimes, this hope was temporarily realized and I would in fact shoot for years with no interest in upgrading (two good examples: my old Nikon FG-20 and my current D610). I like my current D610 more now than I did when I got it. No rose-colored goggles: it lacks some things I'd use regularly like the cool flippy-touch-sensitive screen on my old D5500 and/or the numerous benefits of mirrorless but let's be serious- the image quality of the D610 sensor is just fantastic. I seriously have no want or need for anything else as I type this. It won't last (for me)! The state of the art will advance I will look to spending an uncomfortable amount for a different camera that (temporarily) meets my then-current perceived needs. OR, my needs will simply change. For example, If I shifted to full-on wildlife photography only- I would start trying to figure out how to swing a D500 or (more likely) seriously consider the D7500. Heck- I've looked at the D7500 seriously recently but concluded it wasn't 'better enough' wildlife shooter (even being a crop) to warrant adding as a supplement to the D610. Still, one goes on sale or a nice used one comes along in a year or so- who knows? Nikon comes out with a 'real' mirrorless DSLR- who knows? I'm guessing that's pretty standard- do you have a different experience? Someone, who (for example) bought an F2 brand new years and years ago and still uses it as their main shooter? Even crazier- still shooting your Pentax K1000 from the 1970?