This is a BAD time of year for fleas.
The outdoor fleas are looking for an winter home inside, the colder it gets,
the more they congregate outside your doors, where they feel warm air leaking out the most.
So even if you used drops, they will jump on your pet OR YOU, hitch a ride indoors and colonize in your rugs.
That is why when we first walked through this house, and I saw it was all hardwood or tiled floors, I had to have it.
Also, it has central vacumm, which means anything you suck up, goes outside and stays outside,
nothing goes through a wimpy filter only to get blown into the room again.
Wall to wall carpeting sux if you have pets. It collects dust, pollen, pet dander and hair,
and no matter how much you vacuum, there is always a LOT you don't get up.
And like I said above, most vacuums have very inadequate filters, no matter how much they advertise how 'hypoallergenic' they may be.
A lot ends up getting blown back into the room as microparticles of allergens.
And wall to wall carpet harbors most pet parasites too.
On a few of my areas rugs I use Diatomaceous Earth sprinkled on and rubbed in with my feet. (just before I go to work)
I leave it on for the day and when I get home, lightly vacuum and/or gently shake the rugs outside just so they don't look powdery.
Most of the DE falls into the base of the fibers and continues to kill fleas even if you don't see the DE on the surface of the rug.
DE kills fleas because it is microscopic sharp grit (all natural NOT a chemical) which gets into the soft joints of the fleas shell,
pierces, slices and dices and makes them literally bleed to death, desiccates them.
DE is harlmess to you and your pets, harmless to fish too and if mixed with food, kills internal parasites too.
I use Frontline or Advantage Flea Drops on the cats and the dog, whichever I have coupons for or happens to be cheaper.
There is also a pill you can buy from the vet that kills all fleas and ticks within 24 hours.
This time of year I put drops on them every 2 weeks til the first HARD frost which kills adult fleas. Light frosts don't kill them.