Within the undergraduate physics curriculum, students' primary exposure to experimental physics comes from laboratory courses. Thus, as experimentation is a core component of physics as a discipline, lab courses can be gateways in terms of both recruiting and retaining students within the physics major. Physics lab courses have a wide variety of explicit and/or implicit goals for lab courses, including helping students to develop expert-like beliefs about the nature and importance of experimental physics. To assess students' beliefs, attitudes, and expectations about the nature of experimental physics, there is currently one research-based assessment instrument available—the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS). Since its development, the E-CLASS has been the subject of multiple research studies aimed at understanding and evaluating the effectiveness of various laboratory learning environments. This paper presents a description of the E-CLASS assessment and a summary of the research that has been done using E-CLASS data with a particular emphasis on the aspects of this work that are most relevant for instructors.