We learned from experience that over time fleas can develop a resistance to one product used over and over. We used Advantage for almost a couple years with success, then it stopped working for us. We switched to Frontline Plus which worked great. Both products work but can loose their effectiveness if used over a long period of time. It’s also important to put both on correctly, on the skin under the fur, not easy with animals with thick fur. We tried the method of bathing the dog with Dawn dishsoap and learned that this actually interferes with Frontline Plus and Advantage working successfully, maybe because of washing the oil from the skin and fur as someone else has mentioned.
It’s also important to get rid of fleas in the yard if your pet goes outside; otherwise, the house just keeps getting reinfested.
Blessings,
Naomi