Well, I'll be 66 years old next month and I'm in general good health. I have 50 handguns plus about 14 long guns. I'm always thinking about selling one or two handguns, but it seems that if I sell one I end up buying two.
My wife and I are fortunate not to need any money from the sale of my guns.
Although I don't shoot the long guns much anymore, I do go to my indoor range once every week and usually take a couple of pistols. One week it might be one of my five .45 1911s and one of my three S&W 10mm autos, the next week one of my seven S&W .45 autos and one of my four Glocks, and the week after that one of my five Makarovs and my CZ-52. You get the idea.
My older brother (70 years old) is a gun guy like me. I have no children but he has two, and although they each owns a few guns, they're not gun nuts. I'm designating (within our family trust) a few specific firearms to my brother (if he out lives me), nephew, two nieces, grand-nephew and grand-niece. That will account for about a dozen firearms. Then they will each get to select a few more in rotation. If there are any remaining, the trust will sell them.
Now, that said, if I get into my 80s and I find I'm not shooting them as much, I will probably sell a few. However, there are several I will never sell, although I don't need to be buried with any of them . . . heck, I'll be dead!