Call it an oldie but goodie.

Once again, fire departments across the country are using the occasion of daylight savings time as a reminder - you really should check the batteries in your smoke detector and, if you have one, your carbon monoxide detector.

The rule of thumb here is - batteries in each should be changed twice a year.

"Generally speaking, when you plug it (the battery) in, the detector will 'chirp' to let you know everything's working properly," said Captain Robert Seeber of the Watertown fire department.

The upside is simple: smoke detectors tend to be reliable protection, and changing batteries is trivial.

The downside is a statistic: 70 percent of all fire deaths occur in homes where there either is no smoke detector, or the one that's there isn't working properly.

By the way, you probably already know this, but daylight savings time means you'll set your clock ahead an hour. We get the hour back in the fall.