Fall back… .
Don’t forget to set your clock back one hour back.
Daylight Saving Time is ending tonight at 2 a.m.; the first Sunday of November.
It is also the 28th year of the Change Your Clock, Change Your Battery program, sponsored by Energizer and the International Association of Fire Chiefs.
In and interview after the Orchard Street house fire in Upton in the spring of 2013 Upton Fire/EMS Chief Ron Goodale stressed the importance of working smoke detectors. “Most people don’t plan on having a fire; we know three people got out unharmed because of working smoke detectors.” Chief Goodale advised changing the batteries in your smoke detectors when you move your clocks for daylight savings. “Smoke detectors are an important safety feature, it’s important to make sure they are working,” said Goodale.
UPTON DAILY 
All smoke detectors will tell you when their batteries need to be changed by sounding the alarm periodically until you change the battery. A smoke detector that does not alert you to a weak a battery will almost certainly also not alarm in the event of smoke.
So periodically changing the battery before it is needed provides no extra protection. My experience has been that the batteries will last from 1 to 5 years in a smoke detector depending on the chemistry (zinc carbon, alkaline, lithium) so by changing them twice a year you are throwing away money, increasing the amount of hazardous waste and not providing any extra protection for you and your household.
Better advice is to press the test button on your smoke detector when you change the clocks back (although you really should press that button weekly to better protect your household).
While encouraging consumers to throw away perfectly good batteries is great for Energizer and other battery makers profits, it is wasteful.
For the best information, read the instruction manual for your smoke detector. I have never seen any manual that recommends changing the battery twice per year. All of them I have read over the decades clearly state that you should change the battery when the low battery alarm sounds.