What should not be included on a drawing unless it provides information needed to describe the part clearly?

Including only essential information on a drawing is crucial for clarity and effective communication. Views serve to provide multiple perspectives of a part, showing its shape and features from different angles. However, if a view does not contribute necessary information that helps in understanding the part clearly, it should be omitted. The primary goal is to maintain clarity without introducing unnecessary complexity.

Dimension lines are essential for indicating sizes and distances, and they are fundamental to the understanding of the part's measurements. Notes can provide additional information that might be crucial for interpretation, such as specifications or material requirements. The title block gives critical identifiers, such as part names, drawing numbers, and revision history, which are key to understanding and referencing the drawing correctly.

Thus, only including views that add clear, necessary information aligns with the best practices of technical drawing, where the focus is on simplicity and effectiveness in conveying important details about the part.