December

USFA: inspect holiday lights every year before you put them up; throw away strands with frayed or pinched wires; read the manufacturer's limit on how many strands to connect; keep candles at least 12 inches from anything that burns. CPSC: never string together more than three sets of incandescent lights, never overload outlets, and watch the ladder: about 160 decorating injuries a day happen in the season, nearly half from falls. Set it on stable ground, keep it away from the power lines, have someone hold it, and never stand on the top rung. ESFI: outdoor lights and decorations go on circuits protected by GFCIs, only cords and decorations marked for outdoor use go outside, and everything gets turned off before you leave or sleep.

USFA: water a real tree every day, because a dry tree burns very hot and very fast; keep it at least 3 feet from heat sources; and get rid of it after Christmas or as soon as it is dry.

Open the cabinet doors under sinks on exterior walls, drip the faucets served by exposed pipes, keep the garage closed, hold the thermostat steady, and never thaw a pipe with a flame. The full Red Cross routine is in January. Keep a towel and the number of a licensed plumber where you can find them.

CPSC's winter release repeats the summer rule: generators run outdoors only, at least 20 feet from the house, exhaust pointed away from windows, doors and vents, never in a garage even with the door open. Two more CPSC rules: never plug the generator into a wall outlet to feed the house wiring (backfeeding can electrocute utility workers and neighbors; the safe connection is a transfer switch installed by a licensed electrician), and turn it off and let it cool before refueling, because gasoline spilled on a hot engine can ignite. Never store the fuel in the house. Test the CO alarms the same day you fuel the generator.

Three dates decide next year's list. Smoke alarms: replace the whole unit at 10 years (USFA). CO alarms: per the manufacturer, or every 5 years by the CDC's default. The water heater: DOE says 10 to 15 years is typical, and IBHS says three quarters of all water heaters fail before year 12, with leak risk rising sharply from year 5. Write the install year of each on a strip of tape on the unit, and put the replacement year in the calendar.