1. A medical device system, comprising: a storage device configured to store current posture state data describing a posture state in which a patient has previously been classified; a sensor configured to sense one or more signals indicative of at least one of a posture and an activity state of the patient; and control logic configured to process the one or more signals in a selectable manner that is based on the current posture state data, and after processing of the one or more signals in the selectable manner, to utilize the processed one or more signals to classify a patient as being in a posture state, wherein the posture state in which the patient has previously been classified is a posture state in which the patient was most recently classified.