Did you know that if dust gets in your smoke alarm, it can cause it to go off? Not just the chirping - you need a new battery - sound, but actually go off? We didn't know that. Now we do. (It actually says on our smoke alarms that we are to check the battery weekly and dust monthly .... not proud of the fact that we change the batteries when they chirp and it's the first time they've been dusted in the 5+ years we've lived in this house...)
We also didn't know just how quickly all six of us could get downstairs ready to head out the door if the smoke alarm were to go off - until last night. Now we do. It's pretty quickly.