In a bar between universes, watching the stars explode from her booth, there is a young woman drinking a steaming mug of creamy tea.
"I have to hold the spell design in my head and the more I practice it the more I find ways to put parts of it together in chunks. It gets faster per cast and I have more, sort of, room in my mind to think through spell anchor specifications at the same time. I'll be slower next time because I'll be starting to get worn out and have to be careful." (They've long since reached a level of informality where they're not tracking minute-to-minute changes of this magnitude in who owes whom how much, and most moral places just trade information for free. And he kind of wants to be friends.)
"Huh, like how you'll speed up if you sing the same song fifty times."
"I think you're not supposed to speed up songs just because you've sung them before but maybe so."
"Well, you're not supposed to but it happens if you don't have a way to keep time."