LPT: go look at your furnace and hot water heater, and note where the gas shutoff valve is. This can be the difference between a ruined furnace, and a burnt down house.

I have used this knowledge twice in my life now to prevent fires from getting out of hand and becoming devastating.

When a fire starts from your furnace or hot water heater, it's usually because of a fault in the gas valve. Shutting off the gas valve will kill the gas feeding that fire and prevent your entire house from burning.

Also, buy a fire/smoke detector/s to place near your furnace and heater.

(obviously none of this applies if you don't have gas heating)