Which of the following is NOT one of the three factors to consider when choosing parts?

When determining which factors are essential in choosing automotive parts, the focus typically falls on aspects that directly impact the vehicle's performance, safety, and overall repair costs.

Cost is a significant factor, as it greatly influences both the total repair expense and the decision-making process for both appraisers and repairs. Reliability is also vital because the parts selected must perform consistently without failure, ensuring the vehicle operates correctly and safely over time. Safety is another critical aspect, as any components used in repairs need to meet specific safety standards and contribute positively to the vehicle's safety performance.

Weight, while it may be a consideration in some contexts, is not typically seen as a primary factor when selecting parts. It may have implications for the handling characteristics of a vehicle or fuel efficiency, but it doesn't hold the same level of importance as cost, reliability, or safety regarding part selection. Thus, it stands out as the correct response to the question.