I’ve used this product for over 20 years. I have always had 2-6 dogs my entire adult life and have never had fleas in my home. My dogs are free to come in and out through a doggie door. I live in a very wooded area. I treat my dogs with sentinel and use flea stoppers in my house on all carpet areas. I treat the carpet with flea stoppers every two to three years and have never seen a flea in my home in over 20 years.