well in all honesty you may not need one...BUT if it lasted this long wouldnt you just want the whole situation done for the same length of time it lasted so far? It's kinda a preferance deal, maintenance item kinda thing. Its like replacing one light in the dash cause its burnt so someone pulls the whole thing and you dont want to replace the others...2 days later you have to pay to do it all again. I know it dont really make sence to you as it didnt to me either when I first got this BMW thing. Kinda like peridocly replacing hoses. water pumps, thermostats etc even when theres absolutly nothing wrong with what is in there right now. I hope in some insignificant way this can penetrate and cause you to think about your BMW "outside the box"