athass_prkr
Do not include magical exhaustion. It's not a thing, there's no such thing as a "mana pool" in Harry Potter. There is only one thing that matters in magic in Harry Potter and that is intent, that's why fully fledged wizards do not need wand movements or incantations as they only exist to help you focus your intent. That's why spells like the killing curse only require you to truly intend for someone to die as stated in the books that even if Harry used avada on Barty jr. (fake moody) it would at most result in a paper cut.