Not sure about Advantage, but Frontline has a guarantee. If you use it as directed, and your home becomes infested with fleas, they will pay for extermination or refund what you paid for the product.

We've tried everything! Our dogs got fleas last summer & no amount of Advantage, Frontline, flea collars, regular brushing, groomers, & cleaning their space has gotten rid of them. With the warm winter, flea season hasn't started earlier, it never ended!

I have found that in addition to using a flea/tick insecticide on the dog that regularly applying an insecticide to the yard really helps.

You might try treating your lawn if the fleas are bad but make sure you read if harmful to pets. Flea eggs can be brought in on your shoes so taking them off before going in the house is good also. If you have fleas already don't bomb your house as its poisonious to everybody. You have to vacuum daily(I know everyone hates vacuuming) for 30 days straight to get all the flea eggs and fleas and this is what breaks the flea cycle. Of course making sure all your animals are treated every 30 days is a must also. Unfortunately large dogs are tough with fleas but being vigilant usually works. Also they sell a product called CAPSTAR available in Petstores and used by vets that kill all the fleas on the animal within 1-24 hours. You can safely treat your pet with Frontline or Advantage after 48 hrs of giving this pill. Frontline also sells a spray for bedding etc. expensive but works so in the long run saves you money.

Here is a tip from a cat expert on how to rid your house of fleas-
Spread a 50/50 mix of table salt and baking soda on your carpets and furniture, wait 20 minutes and vacuum very thoroughly; dispose of the bag outdoors immediately. Wash all bedding in hot water. Repeat this process once a week for four weeks to catch fleas in all life stages.
Good Luck