The answer to 'how to maintain thermostat' is to regularly clean and inspect your thermostat to ensure it is functioning properly. This includes wiping down the exterior, checking the batteries, and testing the settings to make sure the thermostat is accurately controlling your HVAC system.
It's recommended to clean your thermostat every 6 months, or as needed if you notice any issues like inaccurate temperature readings or unresponsive controls. Always turn off power to the HVAC system before performing any maintenance. If you're uncomfortable doing this yourself or encounter any problems, it's best to call a professional HVAC technician for assistance.