The value of research using lab animals hinges on the ability to carry out experiments in a tightly controlled environment. Diet, caging materials (e.g., cages and water bottles), and other environmental variables have the potential to create serious disruptions in animal studies. The authors describe the inadvertent damage of polycarbonate caging materials during the course of routine cagewashing, providing an instructive example and illustrating the importance of defined and controlled environmental conditions in biomedical research.