Final answer:
The common reasons for a color change in hair include covering gray or white hair, enhancing existing hair color, and creating a fashion statement.
Step-by-step explanation:
The common reasons for a color change in hair include covering gray or white hair, enhancing existing hair color, and creating a fashion statement. These reasons all involve changing the hair color to achieve a desired look or to restore the original color. Making the hair appear shorter, however, is not a common reason for a color change.