Wastefulness is the habit of using more of something than you need, or throwing away things that still have value. When you leave all the lights on in empty rooms, use ten paper towels to dry your hands when one would work, or throw away a pencil just because it needs sharpening, you're showing wastefulness.

Wastefulness matters because resources are limited. Your family has a budget for groceries, your school has a budget for supplies, and the planet has limited forests, clean water, and energy. Someone who fills their plate with food they won't eat, leaves the water running while brushing their teeth, or prints out twenty copies when they need five is being wasteful.

The opposite of wastefulness is thrift or efficiency: using exactly what you need and making things last. A wasteful person throws away a notebook after using three pages. A thrifty person fills every page before starting a new one.

Wastefulness can apply to more than just physical things. You can waste time by procrastinating when you should be working, or waste an opportunity by not trying your best. The key idea is always the same: something valuable is being used carelessly or thrown away for no good reason.