Ideally, smoke detectors should be placed in every room in the home. But at the very least, have a smoke detector in each bedroom and common area, as well as rooms in which fires are more likely to start, such as the kitchen --- but not too close to a stove. Smoke detectors should be placed as high as possible on the wall because smoke tends to rise upward, but be sure to also give 6 to 12 inches clearance between the smoke detector and the junction of the wall and the ceiling. Never install a smoke detector near a heating or cooling vent or too close to a shower. Normal heated air and steam in these locations could lead to nuisance false alarms.
Most homeowners are familiar with battery powered smoke detectors, but homeowners are also turning recently to a newer type of smoke detector technology that hard-wires the detector into the home's electricity system and only uses batteries in the event of a power failure. Some communities require hard-wired smoke detectors by law; for other communities, it is simply up to the homeowner to decide what type of smoke detector to use. Hard-wired systems are more reliable but are more expensive to install and maintain.
Battery powered smoke detectors should be checked monthly. Every smoke detector comes with a "test" button that you can press to ensure that the detector is getting enough power from its battery. Batteries should be changed at least once per year or any time you hear the low battery warning signal from the detector itself. Battery backups in hard-wired systems should be checked and replaced just as regularly as is necessary for traditional detectors.
Among the most important considerations to make when using smoke detectors at home is that you are in full compliance with local safety laws. Laws and regulations mandating the use of smoke detectors in homes and businesses range from the international all the way down to individual communities and subdivisions. Consult a local government official to inquire about the safety regulations that apply to the smoke detectors used in your home.