It is recommended that you should test your smoke alarm every month and that your smoke detector's batteries be changed, at a minimum, once a year. Daylight Savings time provides a convenient time to perform both tasks since you'll be going through your home changing the times on all the clocks. Most fatal house fires occur when people are sleeping, so a working smoke detector is key to your family's safety.
When changing the batteries on your detectors, be sure to check the detector's manufacture or expiry date. If no expiry date is listed, smoke detectors should be replaced 10 years after the date of manufacture. If you can not find either an expiry date or a date of manufacture, your smoke detector is most likely older than the standard that required them to be dated and should definitely be replaced. Smoke detectors contain materials that degrade over time and, therefor, they tend to lose their sensitivity and effectiveness over time. This is also a good time to clean up your detectors. Smoke detectors should be wiped down with a damp cloth, being sure not to use any solvents or strong cleaners on them. Dust can be gently blown out of the interior of the detector. Testing of alarms should be done after cleaning.
Smoke detectors should be located throughout your home with at least one on each level, including the basement. Because smoke rises, it is recommended you place the alarms on the ceiling. Avoid ceilings near bathrooms, heating appliances, windows and ceiling fans. Smoke detectors should be interconnected for the most protection, so when one detector goes off, they all go off.