I have experienced about all the same issues related by others in my years with dogs, but since I switched to "K-9 Advantix" 2 years ago I have not found one single tick imbedded on either dog. I have found a couple crawling on the dogs and me right after coming in from the field, but not one has dug in, on them anyway. Before that I used Top Spot and Frontline. But, I think they all lose effectiveness over time as the bugs most susceptible to whatever new snake oil die off and get replaced by heartier critters. Just food for thought.
