Keep em and save em unless there’s a reason I dislike it or its something that I just don’t use.
Worst case, I end up with a safe full of guns and one day pass them down to children, grandchildren, etc…
Some of my most cherished firearms were those given to me by my grandfather.
Keep the old reliables is what i do.
I treat my older firearms like the Triarii - last line of defense.
My M&P45 is my night stand gun right now. It was a great carry piece, especially for a full size gun, but I wanted something smaller and with higher capacity, so I got a Glock 19. But 3 years, 2 police academies, thousands of rounds, an Apex trigger upgrade, IDPA match, etc…I’ve invested too much time to get rid of this gun. It’ll also be my carry gun for when I travel to ban states to visit family.
I started shooting in the early 1980’s and started with 1911’s and smith revolvers. I then proceeded to go through every phase of gunning as I like to say- beretta hk sig more 1911’s glock etc. after every phase I found my self reverting back to a few standbys- smith revolvers a 1911 or two and a couple glocks. I am at the point in my life now where I see no reason to run out and buy the flavor of the week. Do the guns I have run? Check. Do they put the bullets on target in relation to the sights? Check. Sort of like the military rifle trial where they announce the next heir apparent to the m16 series then decide it really is not worth changing. You reach a certain point when new is not actually better. Over time my pistol battery has gone from over forty pistols down to under twenty now and while I used to sort of collect, am down to the conclusion I keep only working guns. Even at under twenty I see 6 or8 that could go away with no heart break
Yep, for the most part I don’t sell guns. There’s always room in the collection for 1 more…
Never, if you must part with it give it to some one who deserves and could use it. Wife, child, parent, old friend. A dependable gun is not one worth selling, it is worth giving away if it may save the life of some one you love.
My Glock 27. I am hopping that will change soon 
Second that. With the exception of curios and plinkers, I won’t have an unreliable or ill-fitting handgun on the place. But I do have some very serviceable antiques around, with another century left in them.