Watertown Fire Rescue is reminding area residents to change the batteries in their smoke alarms and carbon monoxide detectors this weekend when they change their clocks. Smoke and carbon-monoxide detectors can be tested by pushing the test buttons, and families should take the opportunity to practice escape routes. Home fire fatalities peak between 10 p.m. and 6 a.m. when most families are sleeping. It is a good idea to replace smoke detectors every 10 years and replace Carbon Monoxide detectors every 5-7 years.