That is a good question. Well here is one answer. To be on the safe side two times a year. That is the recommendation of all fire departments. I do it ones a year some time and it is OK but I should do it twice a year. Please do not wait until they start beeping it will drive you crazy before you get them changed because they will most always start beeping at night. It must be some kind of law or something! If you are not able to change you batteries give us a call. We can do it...

That is a good question. Well here is one answer. To be on the safe side two times a year. That is the recommendation of all fire departments. I do it ones a year some time and it is OK but I should do it twice a year. Please do not wait until they start beeping it will drive you crazy before you get them changed because they will most always start beeping at night. It must be some kind of law or something! If you are not able to change you batteries give us a call. We can do it...