We had terrible fleas last year, from a warm winter and a wet summer. I tried diatemaceous earth, and that didn't work at all, and we also tried a few different essential oils, like eucalyptus. Finally, we bought Revolution and haven't had a problem since.

We had used Advantage for years, but apparently they changed their formula, and it abruptly stopped working. Lots of posts around the internet about it. Revolution is the only one that worked for us.