"What you wanna go messin' around up in the mountains for? Ain't nothin' up there but snow, and wolves, and more snow.
Yer lookin' for the old tomb? Take my advice, boys. Let that tomb alone. There ain't nothin up there you ought be messin' with. No money, no treasure, no fame, just ice. And death."
A possible answer to what happens to spells when a mage dies. If the spell is strong enough, say and enchantment or other permenant effect, part of the mages spirit may become lodged in the magic. It may be a way for items to gain some kind of intelligence, but a mage who has knowledge of this fact would be very hesitant about enchanting anyone or thing. He might have other plans for his afterlife than counting the change in your bag of holding.
Preists, I think, would have this sort of thing covered.