It's known that shamans gain their power through asking the elemental spirits and borrowing it, they don't subdue the power and control like a mage or warlock would. My question is, do they have to ask every single time for when they want to cast a spell? Must they ask for every lightning bolt, every laval burst, every healing wave? Or are they granted power over an element, are free to use it whenever, but if they break the balance it is revoked?