Limits to powers? I like to think I'm fairly reasonable, but just in case. What are no-go territory?

Ages? I can't imagine a 7 year old going on missions, or a 97 year old

Geography/History?

How widespread is magic? Does everyone have it, or is it a common but selective type where Mages are widely recognised but not as common as non-mages?

Food for thought, Just of the top my head.