I use it regularly, so most of the time, I don't notice it working...........it just does. However, when we've been "in the sticks" with the dogs and they come back with a load of ticks, I bathe them, then frontline them in the evening, put them to bed. In the AM, I put 'em out front on their leads (so the critters won't get in the back yard, front is treated), then wash out their kennel/carriers. Then I launder their bedding, put it all back together, and bring them in. They're fine after that..........I don't even have to look at all those little eight-legged things.