I'm a big believer in this. My needs and interests changed over time and what I just had to have 20 or so years ago sat unfired in the safe after the initial interest waned. My safe was over stuffed with a very eclectic and really not very useful "collection", my ammo box was pretty bare, and I had no money to buy the type of guns I was now interested in.
Not being a wealthy man I can only justify devoting a certain amount of my resources to unused possesions, so I sold or traded off the safe queens and used the proceeds to get guns I would use. I now have far fewer guns, but all are very good quality and I have a decent amount of ammo so a days trip to the range won't exhaust my supplies, as used to be the case. I also shoot more often, and shoot better as a result. Imagine that!