With my hearing aids, I get free battery replacements on the NHS. Bonus, the nearest place to swap is my literal doctor's office in the village. So I'd mentioned to youngest that I had a pack ready to get swapped, and she volunteered to trot it down and see if they'd let her trade it for me. They sent her home with two fresh packs -- good kid. But yeah! NHS does some things nice, hee hee. I get fresh batteries free, and they recycle the old ones for me.