"The most important part is to never unplug the batteries, replace the batteries, test the alarms monthly. So many people die in fires not because they didn't have an alarm, but because they didn't have a working alarm," said Williams.
Williams added, interconnecting alarms is a great idea because if one goes off they all go off, giving extra time to get to safety.
If an alarm is 10 years old it should definitely be replaced. Optimal replacement time is four to five years, however some alarms last longer. To tell when to replace your alarm look on the back of the box, said Williams.
"You can and should check and test alarms monthly," said Peg O'Brien, public relations for National Fire Protection Agency.
According to NFPA's Web site, "Tens of millions have alarms, but not enough for proper protection."