In the real world I write software. If my work is not backed up, it's possible to lose weeks of work in the blink of an eye. My employer creates backups to prevent this and I also have extra personal backups because, well, things happen at the worst possible moment and all systems can and will fail at some point. This I have learned the hard way.
Either because it's my nature or because I've been writing software too long, I like to have backups for lots of things. I have backup milk. It's milk in a box that can sit on a pantry shelf, but I keep it in the refrigerator so that it will be cold if I need it. If I run out of milk and a storm is coming, I can avoid the supermarket, because for some reason when there is going to be a storm, people swarm to the supermarket and it's really worth avoiding going anywhere near the place. I also have powered milk, but that's the backup of the backup and is for real emergencies like famine, flood, quarantine or needing milk to make brownies when the store is closed and there is no milk or backup milk.
I've been lucky enough to never loose power for much more than a day, but my flashlight and candles are ready. Because I heat the house with oil and my oil burner needs electricity to operate, I feel I need a backup source of heat. I have a fireplace for backup and wood to fuel it. I haven't lost power recently, but sadly the big iron monster furnace in the cellar is breathing it's last.
It's not surprising that the furnace, or as I recently learned to correctly call it boiler, is kaput. I think it's older than I am and I'm older than dirt. I'm told it originally burned coal and was retrofitted to burn oil. No one I know has burned coal around here for 50 years. The house was built in 1928 and the boiler could well be original. If it's lasted 77 years, I guess I can't ask for more and I know it's replacement will be more efficient. So while I'm waiting for a replacement. I using the backup furnace called a fireplace and I'm burning the backup fuel which I already had stored by the front door...just in case
If you think the fireplace isn't keeping me warm enough, don't worry. I also have a little electric heater, because....well, you never know when you'll need it.