If you have have used both Costco and Rayovac size 13 hearing-aid batteries, how do they compare for battery life? Thanks.?

Costco Hearing Aid Batteries

Both are bad brands -- and I have come to believe

that Kirkland cells are made by R-O-V anyway.

I have completely and permanently stopped using Kirkland cells.

Best cells overall:

Renata (made in Switzerland) and Varta (made in Germany).

Radio Shack did sell some high-grade ones in the past,

but I don't know whether their current line is any good.

Energizer is good, followed at some distance

by Duracell (too many leaks).

Panasonic and Sony do well enough to satisfy me.

batteries of the same chemistry will have identical performance characteristics. hearing aid batteries are air cell, so the battery is not active until the tab is removed. this means the battery will give factory fresh use no matter how long they have been stored. i have used air cells long after the suggested expiry date with no degradation. this is not true of other battery types, like silver oxide or alkaline. there the initial charge starts to diminish during storage because of self-discharge. quality of manufacture can affect the long term self discharge rate.