But none of those were sorcerers - it's pretty clear from the books that it's the Will and the Word that makes you immortal. After all Beldaran (Pol's sister) died of old age because she wasn't a sorcerer.
I said potentially because the book does show that sorcerers sometimes grow tired of living - Belmakor and Belsambar being the examples - and commit suicide.
Wow, I really have retained an awful lot of Eddings trivia