I have never sold a gun.
I expect my children/grandchildren to get them.
There will probably come a time when I start giving them away just to make the estate process simpler.
I considered that, but I decided it was better to set aside "special" guns for my kids rather than trying to maintain a large collection. Even so, they're going to each have a decent collection if I never buy another one. I have for each: 2 22lr revolvers, 2 32 revolvers (one vintage 32SWL and another vintage 32-20), 2 38s (K38 Masterpiece, and a nearly NIB 10-7), and 2 44mags (Redhawk and 629). I only have one rifle, so I'll need to add another one at some point. I have plenty of shotguns for them as well.
Three things I try to do with my guns for their benefit: I don't buy trash and I try to get the gear to reload for each caliber and have some ammo set aside that won't be shot. That way, along with each gun goes some ammo (especially nice for the two 32s) and the tools to load more. Finally, I make sure I've used them so they're not just guns "dad bought", but guns "dad used and cherished". That's another reason I let some go, I just don't care about them. The ones I have now have meaning to me and I hope that translates to meaning for my kids.
Chris