I've been to one or two trainers for Destruction magic already. Since then, if I go to another trainer (different skill) of a level that I've already trained at, the dialog says I've maxed out my training (5/5).
So, it seems to me that you can only train five times at a given training level (Common, Expert, Master) across all skills. However, given how many different skills there are in the game and how many Trainers there are, this seems rather crippling to me.
Can someone explain exactly how Training works? Is my above presumption correct?