When Should You...

Replace the vacuum cleaner bag?
When it smells bad, or before it is so packed that suction is impeded. And definitely before it reenacts Mount Vesuvius.
Replace brooms?
When the edges are bent, broken, or splayed. Or when the broom is irreparably filthy.
Replace a sponge mop?
The minute the sponge loses shape and dimension.
Use paper towels instead of a cloth?
When you're cleaning up something that could contaminate — juice from a raw chicken, for example.
Use a feather duster?
Never. Real feathers can scratch surfaces, and dust tends to be relocated instead of removed. Use an electrostatic dust cloth or a rag instead.
Wear goggles and a dust mask?
Anytime you tackle a dusty area — especially the attic, a fireplace, or the basement. If you're asthmatic, use a dust mask whenever you clean.