You might not be alerted to a fire if you have too few of them or they're too far away. Put them on every level of the house, inside each bedroom, and just outside any bedroom areas, too. Experts recommend that you connect your smoke alarms so when one goes off, they all do. That helps if someone has a hearing problem, has headphones or earbuds on, or is doing something noisy (like using a hair dryer). Smoke alarms aren’t intended to tell you where the fire is -- and remember, fire can spread quickly -- but to warn you to get out ASAP. Test smoke alarms once a month, change the batteries every 6 months, and replace each device every 10 years.