I'm in the process of downsizing now while these things still have some market value. While the child in me does crave to be surrounding by all of my favorite pieces and to be able to recreate any scene from my favorite movies whenever I want, not only do I not have the space to display or properly enjoy them all, I'm also to the point where my priorities have shifted away from collecting. I still have quite a bit of stuff, but a lot of those things are directly related to having examples for my business, but at some point those will likely be liquidated in time too. The older I get the less this stuff means to me.
I do mean to complete a list of values, descriptions and places to offload my collection for my wife and other family members in the unlikely event of my early demise. I've seen thousands of dollars in items given away for free or for pennies both with my late stepfather as well as late father in law and I'd at least want my wife to have the money and get the value from it rather than give away what could potentially be worth something. Props and collectibles are cool and all, but ultimately they're just things and won't matter at all when I'm gone. My rationale is that if the funds from their sale can help my family, then all the better.
The other thing to consider is to sell off pieces while they still retain any value as well. I mean if we're being honest about it, none of us are getting any younger here and the IP's that we cherish so much will die off with us, no matter how many times we hear arguments about how our kids love this stuff, they don't love it the same way and with the same intensity that we do. My father loved the Lone Ranger growing up. I enjoyed a few action figures of the Lone Ranger I had as a kid but I haven't thought about the character all that much since then. The same goes for any of my favorite films and shows. I don't expect or even plan that my potential future children will even like, much less love, what I do and why should they? With that comes the desirablity of the props from said IP. Star Wars for example doesn't sell like it used to. So if you're hoping that your massive collection will be worth a fortune by the time you're dead, even the best measures for you to document your collection for your family to offload for cash, may not necessarily yield the net worth of what you paid for it.
I think it's wise to plan for the future of your collection. As much as these things are a treasure to us personally in our lives, they mean nothing to those around us who aren't interested and at worst become a burden for our family who is left to get rid of it when we're gone. So plan, plan ahead!