Intriguing. I would’ve thought that years of use might well fortify a charm, the way a well-used mortar takes on the oils and flavours of years worth of crushed seeds and spices… or the way the stones of the riverbed get worn smooth, making the passage of water over them ever easier. So perhaps (in some kinds of suitable materials?) the passage of magic through a charm over and over again might in fact imbue it with a kind of magic of its own, surely?

Hmmm….. That’s quite an idea.

Silly me, thinking of batteries when magic is of a more natural origin.

I’ll have to revise this.

Revision complete! Thanks for the idea!