I think I have about 100 - 120 un - built kits and about that many built kits. When I get to the point I cannot build them anymore or lose interest in the hobby, I will start selling the kits, tools and supplies. The kits that are built, I imagine the kids may take a few that mean something to them or to have a memory. The rest of the built kits, tools and supplies will likely go in the estate sale. If anything is left over after the sale, I imagine it will be thrown away. The thought of a lot of that stuff being thrown away makes me a bit sad, but I will not be around, so however my wife or the kids want to take care of this stuff is up to them.
I know of a person who put in his will almost all of his possessions and he expected his heirs to keep this stuff. As I state above, it is sad to think about some of this stuff being thrown away, but I cannot do to my family what the person I knew did to his.