Tip: With winter approaching and heating systems and fireplaces in use, it’s a good time to make sure that your smoke and carbon monoxide detectors are working properly. Have you tested the batteries recently? Testing the batteries is a great item to put on a monthly home maintenance checklist. And know the age of your smoke detectors because those are items that should be replaced when they’re 10 years old, according to the U.S. Fire Administration. To see how old it is, you can check the back of the smoke detector for its manufacture date.