I’m guessing our cat has had fleas since mid-July of this year. Never dealt with this in our lives, so we had no idea she had fleas for so long and was treated by our vet 2 months after (mid Sept.). By then, I’m sure we had many eggs, larva and pupae in our home. The vet treated her with Revolution and an exterminator was in our home at the same time we had the cat at the vet. He said he used Precor. The fleas were out of control, so 3 weeks later, we used a spray called Vet-Kem (this product is an IGR + adulticide, I believe) that we bought at the Vets.