How long does a hearing aid battery last, and does it differ from size to size?
There is no easy answer to this question because it is a function of how much energy it takes to run a particular hearing aid and and how many hours per day that hearing aid is being used. In general, the smaller the battery, the shorter the use life of the battery once installed in a hearing aid but also, the bigger batteries tend to be used in hearing aids requiring a lot more power to run than the small battery powered hearing aids, so, even though they have a lot more energy available, it is used at a much greater rate than in a low power hearing aid.
An analogy might be made with automobiles. I have two Fords and the first one has a 90 horsepower (like a low power hearing aid) motor with a ten gallon gas tank which gets 20 miles to the gallon how long will it run compared to the same car with a 20 gallon tank? If I have the same car but put a 300 horsepower (like a high power hearing aid) engine in it that gets 12 miles to the gallon how long will it run with with the 10 and 20 gallon tanks mentioned in the first car model? Compared to the first car, will it run longer or less? It all depends on the size of the fuel tank, how long it is run and how efficiently the fuel is used.