This has to be one of the most frustrating things to teach.
I have 1 child who "gets it", she is reluctant to part with her money, and you can be positive she always has money.
I have 2 if they have it they gotta spend it.
the littlest, well, the verdict isn't in yet, but it appears she is starting to "get" it.
I'm not sure why one does get it, no she's not the eldest, and the other 2 have no idea.