For the LX500, one 120ML bottle of fragrance oil will last about 30 days on average. For the LX1200, one 200ML bottle of fragrance oil will last about 30 days on average. For the LX3000, one 500ML bottle of fragrance oil will last 30 days on average. For the LX5000, one 500ML bottle of fragrance oil will last 30 days on average. For the LX6000, two 500ML bottles of fragrance oil will last 30 days on average.