I choose not to use anything... If it ain't there why add medication? Flea meds scares me... The instructions tells you to put it on our babies but tells the humans to wash hand well with soap!
I may see fleas occasionally on my kids, but I still don't use anything. When I spot one, I give them a bath and pluck them off as I blow dry them.
I've never spotted more than one or two during the summer. I do spray my girls with Lavender oil - I read there are certain fragrances that naturally repels fleas and it seems to be working for us.
http://www.healthy-dogs.net/fleas.htm
AROMATHERAPY REPELLENT: Using 10 ml. of sweet almond oil as your base, add 10 drops of lavender and 5 drops of cedarwood. Shake well and use 1 or 2 drops spread over the skin at least twice a week to keep the fleas away.
A flea collar can be made by rubbing a few drops of one of the following into an ordinary webbing or rope collar or even a doggy bandanna: eucalyptus oil, Tea Tree Oil, citronella, lavender or geranium. Don't forget to do this weekly.