[DangerousThing]

You may be right and X per day is better from a game perspective.

However, that's not my problem with it. I just can't picture any sort of mechanism that makes it work in the setting. Is there a god of magic enforcing this X per day thing? Does sunrise reset your magic?

That's what I meant about not seeing this in fantasy prior to DnD. As far as I can remember (I haven't read the stories in quite a while) you could do the spells as often as you could stuff them into your mind which required training because it seemed as if magic was somewhat alien to humans (or at least conceptually difficult). And frankly, I never liked the concept, though Jack Vance was such a good writer that I did enjoy the stories for the most part.

I like the idea of using FP. And I use Threshold based magic for Wild Magic in my current game; wild magic is not common and is considered a curse.