Since I have more than one sewing machine and they change periodically, I decided to keep a sewing machine inventory for my daughter's use when I pass away.
I know she will probably want to sell some of my sewing machines when I die and I don't want her to be one of those people that says, "I have this sewing machine for sale, but I don't know if it works or what it does." She can just look at my inventory to see when the machine was bought, how much I paid for it, the serial number of the machine, a description of the kind of sewing you can do with the machine, all the presser feet that go with that machine, and whether there is an owner's manual. Knowing how much I originally paid for it will definitely help her set a price.
I've let her sew on three of the machines, so she knows how to use them and will know that they work, if and when she tries to sell them.
I keep this list up to date with each machine purchased or discarded.