Really. If you check with the vet you purchase the Advantage from, he/she may OK the application of the Advantage sooner than 30 days. (It’s really safe stuff)Another option is a single dose of Capstar, one oral pill, that will kill any fleas and eggs on the pet at the time of the dose within an hour. Capstar only works for a day, and at the same time as the oral dose you apply the topical Advantage which will kick in about 12 hours later and kill any fleas from the environment that jump back onto the cat for the next 30 days. (repeat for 3 months)
The cat that was poisoned with the crappy flea medication I mentioned earlier, died 3 days later.