How to decide

[Jim B]

They sit there for decades, never being shot or moved.

Unless a gun has collector or sentimental value, if I hadn't shot it in decades I'd almost certainly sell it. Put the money toward something else you'll enjoy more. Some guns are easily replaceable. If you later decide you screwed up selling your Glock 22 (or M&P, SIG, Springfield, etc.) it's not too big a deal to go buy another.

I had a Makarov that was a great gun. (Accurate and a surprisingly nice trigger.) I didn't feel like getting myself set up to reload 9x18 (I rarely buy factory ammo anymore) so I wound up putting only fifty rounds through it in ten years. I eventually sold it and used the money to buy a S&W M2.0 in 9mm Luger. I've shot the S&W much more than I ever shot the Makarov.