Battery life depends on several factors, such as how long you use them and how much amplification they are putting out based on its programming. The higher it's programmed, the stronger it will need to output, which will draw more power from the batteries. On the average, about 5-7 days, assuming 14 hours daily operation, and turning the device off at night.
Ensure that the device is completely turned off when not in use
This can be done by turning the device off or completely removing the battery. If you choose to turn the device off, cup the device in the palm of your hand and ensure that no feedback can be heard. If you still can hear feedback when the device is supposed to be off, it is still on. We recommend you remove the battery completely in that case.