Ultrasonic detectors have become a mainstay for studying the ecology of bats throughout the world. Despite their enormous utility to address a wide variety of research and management issues, many factors that impact the applicability of collected data for answering desired questions are often ignored. Here, we review our current understanding of the utility of ultrasonic detectors for the study of bat ecology and highlight areas where additional work should be done. We gleaned information from published studies, as well as from field research experience, and discuss areas that are in need of further research. We highlight topics such as sampling design and how it can impact results, metrics used to quantify bat activity, and identifying bats with acoustic data including how accuracy rates can be maximized. We also provide research questions that when answered will greatly improve the applicability of future studies.