Rechargeable hearing aid batteries are non-replaceable and die after 3 years

Modern rechargeable hearing aids use sealed lithium-ion batteries that are physically fused inside the device and cannot be replaced by the user. After approximately 3 years, these batteries lose about 20% of their charge capacity, dropping daily runtime from 16-18 hours to 12-13 hours -- often not enough to last through a full waking day. So what? Users must send both hearing aids back to the manufacturer for battery replacement, which costs up to $350 per aid ($700 for a pair) if out of warranty. So what? During the 2-4 week manufacturer turnaround, the user has no hearing aids unless their audiologist happens to have loaner devices (not guaranteed). So what? A person with moderate-to-severe hearing loss is functionally cut off from conversations, phone calls, and workplace communication for weeks. So what? This is not a one-time event -- it recurs every 3-5 years for the life of the device, creating a forced obsolescence cycle. This persists because manufacturers benefit from the repair revenue and eventual device replacement sales, and because sealed battery designs are cheaper to waterproof than user-replaceable designs.