Since pencil leads and colour pencil leads will wear in the course of being used and their radius will thus steadily increase, they need to be constantly resharpened to ensure precise drawing or legible writing.

Specialised sharpeners exist for the various types of pencils and leads, from the plain manual sharpener (with or without shavings receptacle) to sophisticated sharpening machines.

Cutters and knives (manual sharpeners) wear out after a while and must be replaced without undue delay.