Excellent question, one that is asked frequently. Often hearing test results indicate that a patient’s two ears are not always equally impaired. However, perceptually a patient may feel that the impairment sounds equal.  When we program hearing devices the computerized software individually programs each ear to give the optimal prescription for the patient. This difference programmed by the software can have an effect on the battery life of each hearing aid. That being said, in general, the discharge of voltage from the battery cells is fairly equal. If a patient notices rapid drainage, that should be noted to the audiologist whereby they can send the instruments to your manufacturer to be evaluated for excessive battery drainage.