Add another voice to the "Why trade a 2-3 year old gun?" chorus. The 15 year old Gen3 Glock 17 I sold to a friend still worked just like the brand new Gen 4 Glock 19 I replaced it with. My 33-year old S&W K and L frame revolvers (they're older than me...
) work exactly like my friend's brand new 617. Come to think of it, my couple year old Colt 6920 carbine operates EXACTLY like the '70s vintage Colt SP-1 my dad had when I was a teenager.
There just haven't been any significant leaps in firearms technology in the last 4-5 decades. We've changed the way they look, but a modern flat-top M4gery is functionally identical to an early Armalite AR-15. If you can take one apart, you'll be right at home working on the other. Same with shooting and using them.
Which makes me cringe and laugh when I see the "gun of the month" on the latest installment of a print gun magazine these days. Advertising and sales demand that the newest SIG, H&K, Glock, Ruger or whatever must be pronounced with superlatives as "the next revolution". Instead what you're getting is a new paint job and a fancy badge put on whatever proven platform the manufacturer uses. OK, the Ruger American Pistol was a new model, but it's still just a polymer framed 9mm or .45 ACP pistol, whose purpose it to launch little bits of metal to put holes in things. In practical terms it doesn't do anything a WWI P-08 Luger or 1911 doesn't do.
As for cars, technology and time DO in fact march on. My last car was a 10-year old Toyota Corolla I bought brand new in 2006. My new car is a 2016 Subaru Impreza. The new car has backup camera, 4-wheel disc brakes (with ABS), more airbags than a Congressional sub-committee, Bluetooth interface (this is probably my favorite feature), AWD with traction control and still gets 30+ mpg. It is a significant improvement to MY driving experience and I plan to keep this car at least 10-years/150k miles like I did the last one. Yes, I'm one of those "fools" who will buy a brand new car off the lot while completely ignoring the depreciation hit, because I'm planning to stick with it until the sales guys don't think I have money or credit based on what I drove up in.