Have you contacted Cognionics for advise on your situation? Dry electrodes do wear out over time, but slowly. My guess is that they rate the number of uses you can expect.
My understanding from someone who examined their dry electrodes construction, is that they are first 3D printed in a flexible plastic, then plated multiple times with various conductive coatings. (Conductive carbon and silver / silver chloride?) If the top layer of plating wears significantly, this will raise impedance.
Other than normal scalp wear, it should not be easy to damage the plating. Unless the care instructions were not being followed.
If your amplifier has a way to measure skin impedance (not just ohmmeter reading of the electrode) – that would be the best way to track over time and report to Cognionics.