2) In case the guy robbing your house forgot a flashlight.
3) So you can vacuum your kids' bedrooms while they are sleeping and not have to turn on the light.
4) Because it's really dark on the floor...
5) Just in case you are afraid of the sun (and lamps).
6) To create the proper ambiance during household chores.
7) So dogs and husbands can see the vacuum coming toward them and move.
8) Just in case you decide to rig the vacuum for road travel...
9) So your children can pretend it's a UFO.
10) To give me something to think about while cleaning the floors.