I have had costco hearing aids for 5 years. The weakness in this this particular aid is that the battery door is used as an on off switch, and since it is flimsy plastic it frequently breaks, and the repair requires that the hearing aid be recased.
Each of my hearing aids has had this problem 2 or 3 times, at a repair cost of $135. Yesterday, I took in a hearig aid again that had a broken battery door, and was told that they could no longer be repaired, because they were 5 years old, there solution, buy nw hearing aids.
So keep in mind that although it is otherwise a pretty good hearing aid, it is only a 5 year lifetime. Meanwhile I am using cellophane tape to keep the battery in place.