Final answer:
It is generally recommended for systems with command latencies over 10 seconds to provide visual and auditory indication to the user when the task is completed, which can enhance user experience.
Step-by-step explanation:
When considering user experience in system design, especially when concerning command latency, it's generally seen as good practice for a system to signal to the user when a task has been completed, especially after a noticeable delay. Given the scenario that a user's command latency goes over 10 seconds, the system should indeed provide a visual and auditory indication once the command is completed. This not only acknowledges the system has finished processing, but also serves as a signal for the user to continue their interaction with the system.
Additionally, for a system to be user-friendly, responsive feedback is crucial so that the user is not left wondering whether their input was received or actioned upon. Therefore, the inclusion of both a visual and an auditory indication can significantly improve user experience during instances of high latency.