Nods. With the thing you said above it makes more sense to me, heh.
What I'm confused on, then, is how making a spell permanent means you can use it without stamina, as Crow said. Why is that, and are there limitations to how often you can use the spell if you do that?
If you buy an expendable charge for the spell does it mean that you 'have' to use that charge next time you cast it from the item, or can you hang on to it until a desperate situation, and cost at Full Stamina before & after using the expendable charge?