In the College of Winterhold, the professor Sergius Turrianus can give you a quest where you go to a random person and pick up an item (as well as a quest where you give him some soul gems). My question is: is it possible to ever "complete" these quests, or will he continue to give you them forever (even after he starts giving you the same people over again)? By complete I mean he will have no more fetch quests left for you to do and will never give you the chat option to do them again.
Also, if it is possible, what is the "ending" dialouge he gives you in congragulations (if there is one)?