Does a cochlear implant get scarred over and stop working after a certain number of years?

Should not: But as you can imagine with any electronic device, malfunctions can occur with time. Your implant surgeon should be able to advise you, but one implant should last 10-15 years. If you are having trouble with your implant, of course contact your ENT for advice.

Unlikely: Implants occasionally do require examination and replacement. Seek consultation with qualified otologist/ent surgeon who regularly performs such surgeries.

Yes and no: No man made device will last forever. Eventually everything must be replaced. They still work extremely effectively for many years. A total internal device is currently being tested.

Possible, but rare: The cochlear implant is designed to work for a lifetime and not require revisions or reimplantations. However, there is always the chance of device failure or damage from trauma to the device (this happens more in kids who are not as good at protecting their heads). It is very, very rare for scarring to interrupt the communication between the electrodes and the inner ear (cochlea).

No: Although any electronic device may fail, it is expected to function for a lifetime.

Cochlear implant: Not usually though there have been various device failures in the past. This is exceedingly rare. Cis are very reliable.