The RMS service is not required. It is only needed if you want to monitor and manage your devices remotely.
If you have already added your device to RMS and the 30-day free trial has expired, you will not be charged automatically. To continue using the service, you would need to manually purchase resources. Without purchasing and activating them, RMS will simply remain inactive.
Additionally, do you see any RMS-related notifications in the WebUI? If you are only using WebUI and notice notifications that seem unnecessary, please let me know, and I will forward this to our RnD team to review.