First for a little back story... I have four cats (two males, two females, all different ages, strictly indoor only, declawed front and rear, and all have consumed the same food for life). Until last year, I never routinely put topical flea medication on the cats because we have never had problems with fleas. About a year ago, all my cats went to stay with my mother while I was out of town. My mother has four cats of her own, and has kept all the cats in the past.