There is definitely a sweet spot for collectible value for anything. Early Hot wheels were incredibly sought after 20 years ago, less so now. The Centuri LJII kit will always be sought after by a few people. I predict the new Estes LJII Release will be shoot up in value once it has run its course. You have only to look on ebay for any era Estes Saturn V or S1b kits to see that. I snagged 3 Saturn V kits from Amazon for less than $40 each during a flash sale a couple of years ago (and got free shipping). Seemed like they couldn't give them away. Now look at what they are bringing. I thought once the values eclipsed $100 that I would sell a couple and make a little "motor money". With them going for $150+...I think I'll hold on a little longer.