I've only had to deal with a "flea issue" once - this summer when I had one of Mom's dogs staying with me. It was mid-August and one morning I was rubbing her ears... only to feel... flea dirt.

Oh eew eew eew!
We've never (knock on wood!) had fleas up at the house in CT. But down here, I live in a tract complex that has lots of dogs... and lots and LOTS of roaming cats. So I was probably lucky that it took as long as it did for me to encounter fleas. Luckily, Markie never got them.
So: after freaking out (and lots of googling, and calling my mother), I got Frontline Plus from the local Petco. Oh, and scrubbed Borax into all the rugs and vacuumed like a crazy lady (I so did NOT want any kind of infestation... and I was really worried that my pet rats would get the fleas, as they're trickier to treat). I was also careful about isolating Daisy (the dog) in her crate for a day or two after the treatment - I felt bad about it, but I wanted to keep any bugs as contained as possible. (We took extra-long walks and hung out on the porch to compensate.)
I think it really took two monthly doses to really knock them out. I never found any fleas in the house (even tried the plate-of-soapy-water-under-a-light-at-night trick), but I did find another flea and some dirt on the pooch about three weeks after the first treatment. I freaked again and washed her from nose to tail-tip in Dawn dish-soap and combed her really well, then did the second treatment a week later. After that, I never saw another flea (or found anymore dirt).
She went back to Mom's house in October, a few days after her last treatment. I haven't heard any reports, so it seems like the repeated applications of Frontline Plus (and the dish soap, and the crating, and the vacuuming, and the borax) worked.