Fogging, in the domestic situation, is only meant to be done initially to achieve total disinfection, such as moving into a new home or after illness in the family. Thereafter it can be repeated once every 6 months if necessary, or when the situation calls for it. For example, if a condition being kept under control by the fogging (such as allergies, dustmites, mould) begins to worsen, or if an outbreak of disease or viral infection occurs in the home.