To take this one step further, you can get "insurance" to keep it covered after the 3 year warranty.
Making a long story short, I was in a study and during that time I had the device they gave me. The only problem I had with the study's model was the LED screen not displaying information properly. It wasn't a problem with determining which program I was on as it beeps that info. It was the volume and sensitivity where it would have been problematical (they replaced it). Later, I received my first CI (silver) in the Fall of '05 and it had the same problem which they promptly replaced as it was under warranty. I got my second CI (blue) in Spring of '06 and I had no problems with that one so far. In the state I live, they give you two CIs but my second one which was blue and it took them longer to finally get the "color" approved by the FDA. The warranties for each are basically 3 years from when you receive them. You bet I'll get the extended insurance to cover them. They cost too much otherwise.