This is one reason in particular I stick to two standard case types. The '06 and the .308 necked up or down will load rounds for just about everything with a long barrel I have. When they get bigger or smaller I stick to similar designs, so as to have extra brass in the event it becomes hard to get. Like for my 7mm STW, finding cases at one point in time, when I REALLY needed them was not happening, so I simply purchased a couple hundred in 8mm Rem Mag. A simply neck down and away we go.
In other areas if and when I DO use the parent case necked up or down, these are always noted on the boxes and kept together when cleaned or stored empty. The container is marked as to what they are as well as the loads used in them. This way, should I not be there when someone decides to do something with all things left behind, hopefully they will at least have a heads up on what it is and what to use.