All fire prevention campaigns remind you to check the battery in your smoke detector at least once a year. They are right. It could save your life.
But what do we really know about those little disks on our ceilings?
There are two kinds of Smoke Detectors
The most common are the electric variation detectors. They are designed to detect big flame fires which are rapidly spreading. After awhile, dust accumulates inside and they may become more sensitive; which is probably why they start screaming as soon as you pull your chicken out of the oven or when you're cooking your bacon for Sunday's brunch. The photoelectric smoke detectors are most often installed by companies specialising in safety. These devices are better adapted in detecting slow combustion fires that can take hours before producing flames, like a cigarette fallen on a couch, for example.
Like your morning yogurt, smoke detectors have an expiry date.
Indeed, your home detectors must be replaced every 10 years. Since about two years, an expiry date is visible on the exterior contour of your detector. For ulterior dates, you'll have to go by what you know about them. If you've been living at the same place for the last 10 years and your detectors have never been changed, you know that their time has come. That too could save your life.