It’s good to replace the batteries in your smoke detectors every twelve months, but you should also consider replacing the smoke detectors in your home or business if they are more than 10 years old. Most smoke detectors contain some electronic components, and after 8-10 years the alarm sensors wear out. At that point, the entire unit should be replaced. When you replace the unit, write the purchase date on the inside cover, so that you’ll always know when you purchased that unit.
Generally a smoke detector will let you know if the battery is low. If the smoke detector keeps chirping or there is a blinking red light you might need to change the battery. The smoke detector red light could also indicate that it is over 10 years old and needs to be replaced. A hard wired smoke detector with a red blinking light could indicate there is a problem with the wire connection.
A smoke detector in good working order is an essential component of your home's safety equipment and having at least one smoke detector means that you, your family and your home are safer.