Context: Software testing requires substantial effort in maintaining GUI test scripts, leading to rework or waste. Therefore, it is important to identify the factors leading to waste in GUI-based automation testing. Objective: To identify testability requirements and factors associated with waste from literature and practice. Methods: We conducted a literature review to identify the state of knowledge and a two-phased interview with practitioners to capture their subjective opinions and gather their views on the state of knowledge. Results: We identified 16 testability requirements and 14 factors associated with waste in GUI test automation. We classified each of them into SUT-related, test-process-related, test-tool-related, human and organizational, environment and cross-cutting. Conclusions: Our results indicate that the generic testability requirements identified in the literature are also valid for GUI automation testing. Our study identifies new findings in addition to the existing literature. © 2022 Owner/Author.