Hearing aid batteries normally last 7-14 days when the hearing aid is used 16 hours per day. Performance will vary depending on the style and type of hearing aid technology you are using. All batteries are toxic and dangerous if swallowed. Keep all batteries (and hearing aids) away from children and pets. If anyone swallows a battery it is a medical emergency and you will need to contact the emergency services. Hearing aids come in different sizes and each battery is coded by color. If your audiologist started you off with hearing aid batteries color coded orange, you can buy any brand of battery with the same color coding.