Two days ago my 84 year old mother called to tell me that her Carbon Monoxide detector had gone off. I changed the batteries but it continued to beep. I ended up buying a new one as it would no longer reset. The next day, my mom calls again...her bedroom and dining room detector were going off. Obviously concerned, I had her leave the house and she called PGE. They came quickly and found no issues. They did look at the Carbon Monoxide detectors and determined that they were manufactured in 2011. Apparently, they are only good for 5-7 years. What are the odds that all 3 would go out within a day of each other? Anyway, this is a reminder that you should check your Carbon Monoxide and Smoke Detectors every month and know that they eventually need to be replaced.