When I was a young man and first got serious about guns, it was a case of gotta sell one to buy one. I sold quite a few that I regretted getting rid of.
Over the last 40 years, as my financial situation improved, I've managed to replace the ones I regretted selling. These days I sometimes regret buying one for various reasons. Those I'll sell without thinking twice.
Who knows, now that I'm retired, at some point I may need to sell some of them. But in the meantime, every gun I own will stay right where it is. My sons can deal with them after I'm gone.