A flow generator for delivering breathable gas to a patient, the flow generator comprising a processor coupled with operation sensors and a user interface, wherein the processor is programmed to generate at least one of time-based messages, event-based messages, or both time- and event-based messages relating to at least one of flow generator operation, flow generator service, flow generator use, patient health, peripheral devices and services, patient treatment, and reminders, wherein the time-based messages are generated at predetermined time intervals based on either time of use or elapsed time, and wherein the event-based messages are generated based on signals from the operation sensors, the user interface being configured to deliver the messages to at least one of a display, a flow generator service provider, the patient and a physician.