It might be time to remind your readers that during the winter months it is a good idea to keep their fuel tanks topped up to the brim for the following reasons. Changes in temperature will suck in and expel air in a partially filled tank and the moisture in the air will condense and drop to the bottom of the tank and in time the tank will rust through. Also, in the winter there is always a chance of being stranded for hours and with a full tank the engine can be run intermittently for heating without fear of using the last drop of fuel. But if there is heavy snow do remember to get out and clear the snow around the exhaust so that the poisonous fumes will not be trapped around the car. An old blanket in the boot never does any harm.