Hearing aid batteries last anywhere between five and 14 days depending on the above factors. You will know it's time to replace your hearing aid batteries when the aids start beeping. One solution to save money and make batteries last longer is to purchase rechargeable batteries.
To clarify: you have a main panel with a 60A breaker. That breaker feeds a subpanel which has a 100A main breaker and then some smaller circuit breakers in the sub-panel. If more than 100 coulombs of charge per second flow through the sub-panel main breaker, it will trip and cut power to the subpanel breakers.
If four then first two are the MAX SPACES, the next two are the MAX CIRCUITS (you can use tandems) Next letter, type of panel, L=Main Lug, B=Main breaker. (If there is a number or letter infront of this then that means its a special panel, probably not used on residentials however) Next 3 numbers are the Amp rating.