Hearing aid batteries come in different sizes, with smaller batteries generally having a shorter life than larger ones. The amount of power required to run your hearing aid and the number of hours that you wear your hearing aid will also affect the battery life. In general, with hearing aids that utilize very small batteries (i.e. size 10) you can expect to change your battery every 5 – 7 days; larger batteries may last two weeks or more. Your provider can give you a more exact idea of what to expect, based on the specifications of your particular hearing aids and the battery size used. Batteries are inexpensive, costing approximately a dollar per cell.