ResMed does not recommend using HumidX components if the packaging was opened more than 30 days ago. If HumidX is used more than 30 days after opening, there may be a deterioration in cleanliness, humidification performance and breathing comfort that could affect the safe and efficacious use of AirMini. Please ensure your HumidX and other components of the AirMini system are regularly maintained as per the user instructions.