The service is to refill the air pressure like car tire pressure it will lose air pressure. You shouild do it yourself like tires are you going to ask mechanic to do it for you? Only once a yr ma. Use a manual pump/bycicle pump. just shut the incoming main to the pump and let go the water from your bathroom and empty it where the pipe from the pump to the outlets pressure is zero then you pump the tank to the desire pressure by using a tire pressure guage buy from car accesories shop.