Ihave two hearing aids and only one duracell hearing aid battery.

I am in a bit of a pickle. I ahve two hearing aids and only one duracell hearing aid battery. I will have to go to the pharmacy to pick up another battery. This usually does not happen. My hearing aid batteries rarely go dead on the same day. I only keep one battery on hand. When I put it in my hearing aid, I know it is time to buy another to have handy. I guess I will have to start keeping two on hand, in case this ever happens again.