Why use a kitchen scale?

A kitchen scale is one of the easiest ways to be consistent with your ingredient measurements. It can help you avoid several types of preparation hassles:

Flour is supposed to be sifted before measuring in cups.
Brown sugar should be packed tightly in measuring spoons.
Did you chop your bell peppers the right size for your measuring cup?
Is your onion too big or small?

All of these issues can be completely avoided by using a scale. All ingredients will weigh the same regardless of sifting, packing or chopping.

The scale will really save you if you need to multiply the size of a recipe to serve a very large group. Lets say your recipe calls for one bell pepper, but you need to make three times the size of the original recipe. The volume of three large bell peppers is noticeably different from that of three small bell peppers. If you know the ingredient weight for the recipe then multiplying by three would absolutely solve your problem. You could buy three peppers that are all an average size, but that method will have you more concerned with the pepper's size rather than quality.

Unfortunately, not all recipes list ingredients by weight. My recommendation is to weigh ingredients after you measure them and write it on your recipe card or paper. If you like how it turned out, then use that measurement the next time you cook the recipe. If not, adjust.