How often must cosmetic pencils be sharpened?

The correct answer is that cosmetic pencils must be sharpened after each use to maintain hygiene and functionality. Sharpening after each use helps to remove bacteria that can accumulate on the tip, which is especially important for products applied near sensitive areas such as the eyes or lips. Additionally, a well-sharpened pencil provides a precise tip for better application and helps achieve a more defined look. Regular sharpening ensures the product performs effectively and safely.

While other options suggest different frequencies for sharpening, they do not prioritize cleanliness and effective application in the way that sharpening after each use does. For example, waiting a week or until the pencil is dull may increase the risk of bacterial contamination and result in a less precise application, which is not ideal for cosmetic products. Thus, the emphasis on sharpening after each use aligns best with best practices in makeup application and hygiene.