The primary determinants of control location are human physiological limitations, spatial relationship to the functions controlled, functional groupings, sequential arrangements, and priority of usage/frequency of use. The first four of these are relatively easy to determine, whether through anthropometrics or task/function analyses, but the final consideration is often less straightforward. The relative frequency of use of a set of controls that are primarily driven not by need, but by user preference are often almost impossible to determine before a product is actually put into use. This paper describes a study designed to evaluate the relative frequency of use of the controls available on automotive stereo products. The study focused on experienced users over an extended period of time and a relatively wide age range. Results indicated that control usage fell into several broad groups, with volume control being the most commonly used function.