Smoke alarms
Always have working smoke alarms present on EVERY level of your home. Smoke alarms should also be installed outside every sleeping area (and even outside sleeping areas, as well-- if the door is closed at night).
Make sure alarms are tested monthly and equipped with fresh batteries (they should be changed AT LEAST once a year). Hardwired alarms (those that are directly wired into a permanent power source) still need to be tested and replaced with age (refer to specific instructions).
Get into a routine of checking your alarms the same date every month. Test your alarm according to factory instructions (usually simply hitting the alarm button-- this can be done on a ladder or with a broom handle).
A "chirping" noise indicates an alarm's weak battery. Use a brush and vacuum to get rid of webs and debris on your alarm (follow factory instructions, or course).
In addition to alarms, be sure to establish and practice a home escape route at least twice a year. Ideally, you should try for two escape routes for every room in the house. Remember that smoke and heat rises during a fire, so stay close to the ground. Test doors for heat (by feel) before opening, as there could be a fire in the room behind the door.
illustration: Ian Keusink