For magic, I think there should be a \"Spell Meter/Mana Bar/Magic Points\" whatever, and it recharges at something like, 1 magic pts per second. The weakest offensive spell should cost something like 10 spell pts, and you should begin with maybe 18 spell points.
Magic should be the main weapon of a mage. It should not be a last resort. Therefore magic points should recharge very fast, but slower depending on how much skill the player may have.
Also, it should recharge slower when you have heavier equipment on. You may not even have to set an armor limit of magic use, just make it so that when a mage is wearing plate mail they do not recover, and they recover fastest with a robe.
Ingredients, regeants? No. Torture...
That\'s all I have to say.