I have been using Advantage for about 3 months on my 1 y.o. cat and he still scratches quite a bit. I'm a little concerned because I like to let him go out in the yard with me every once in a while but not if he's going to get re-infested. I thought that Advantage protected against this?? However, even on months when he's stayed in the house, he's still scratching. Any ideas on what else to try?

Are you sure it is fleas? Kitty may have a skin irritation. If it isn't fleas I would ask the vet. I use Frontline.

Both Advantage and Frontline work really well for fleas. One consideration may be that the fleas have to get on them in order to get the pesticide, and it's possible that he's allergic to flea bites. If he's exposed to the fleas, they will die but not before a possible bite that will cause the itching. I would take him to the vet for a good lookover at his skin, ears, and talk about the possible flea allergy.