Analog quantum simulators (AQS) will likely be the first nontrivial application of quantum technology for predictive simulation. However, there remain questions regarding the degree of confidence that can be placed in the results of AQS since they do not naturally incorporate error correction. Specifically, how do we know whether an analog simulation of a quantum model will produce predictions that agree with the ideal model in the presence of inevitable imperfections? At the same time there is a widely held expectation that certain quantum simulation questions will be robust to errors and perturbations in the underlying hardware. Resolving these two points of view is a critical step in making the most of this promising technology. In this talk I will formalize the notion of AQS reliability and relate the question of whether an AQS is robust to the phenomenon of parameter space compression from statistical physics. This naturally reveals the importance of physical symmetries in dictating the robust properties of a quantum simulation. To illustrate the methods I will analyze the robust features of several quantum many-body models to calibration errors during the talk. The methods developed should be useful for guiding future AQS experiments, particularly for identifying the most important experimental degrees of freedom to control and calibrate.