Over 6,000 deaths occur in homes each year. Many never even wake up. A smoke detector is a fire alarm that buzzes when it detects smoke, warning you in time to escape.
Smoke detectors can be either house current or battery operated.
Either kind can do a good job. Make sure the model you choose has been listed by a nationally recognized testing laboratory. There should be a least one smoke detector in every household. Additional detectors will significantly increase your chances of survival. If you can handle a screwdriver, you can install most smoke detectors.