When do I get upgrades?

So, Magicmaker. Fun game. Clever, crafty, colorful, and charming. Lot of fun making odd combinations, seeing what works. Fun stuff. Pyromania is a character trait, not a medical disorder. Goblins are jerks. Loving it so far.

My question is thus: I've seen gamplay videos where people had four material slots for everything, as well as a second spell with four more slots. How do I get those? I understand that they're given as quest rewards (I got a thing that added another material slot to the robe as a reward for, like, the second quest I did), but are they specific rewards for specific quests? Or are the quest rewards randomized every time?

Thanks for the amazing game! Setting fairies on fire will never cease to be amusing.