I'm in the same boat. This is the first year I had to use front line. Like you only found one or two, but they keep coming back. I used the front line and barely get a month out of it and then boom I see one or two again. I know there is not anymore, because I bathe them every other week and also they hardly go out, but it seems as soon as they hit outdoors they come in with one or two. Very frustrating. It's costing me over $106 a month for flea preventative with the six of them. You would think it would be cold enough now for them to all be gone.
Elaine