I didn't have a problem with fleas this year, up till about a month ago. I think it's because it was so ungodly hot and dry. I never even started the flea protection on the pooches until August, and normally I automatically start it in April. Once we started getting a little rain, and a break from the heat every now and then, the fleas flourished! However, I'd rather deal with the fleas, than the heat. Fortunately the Advantix is working as it should!