The answer to 'how to maintain thermostat' is to regularly clean and calibrate your thermostat to ensure it is accurately reading and controlling the temperature in your home. This will help your HVAC system run efficiently and prevent issues like temperature swings or the system running more than necessary.
Start by gently wiping down the exterior of the thermostat with a soft, dry cloth to remove any dust or dirt buildup. Then, use a small amount of rubbing alcohol on a cotton swab to clean the temperature sensor. Avoid getting any moisture inside the thermostat housing. You should also check the batteries and replace them if they are low. Finally, use the thermostat's calibration feature (if available) to ensure it is accurately reading the room temperature.