The frequency of internal and external deworming for indoor cats usually depends on their lifestyle and potential parasite risk.
Internal deworming: every 2 to 3 months.
External deworming: once a month, especially during the warm season and high flea season.
These recommendations take into account the relatively low risk of parasite exposure in indoor cats, but regular deworming is still needed to ensure your cat's health. If the cat regularly consumes raw meat or has other special circumstances, the deworming frequency may need to be adjusted accordingly. When deworming, follow your veterinarian's instructions and the specific directions for the deworming medication.