Hiring an external evaluator is not right for every museum or every project. Evaluations are highly situational, grounded in specific times and places; each one is unique. The museum and the evaluator share equal responsibility in an evaluation's success, so it is worth investing time and effort to ensure that both are clear about the goals, desired outcomes, and critical questions that frame a project, and to consider practical issues that will maximize its effectiveness. In this article, we draw upon a long-term partnership to explore the museum-evaluator relationship from both sides and provide tips for a successful collaboration.