Fleas - Getting rid of them

We have 2 cats and I have never seen a flea on either of them until last week. One of my cats is white so they are easy to spot, and I found one (alive) on her . We applied frountline to both cats and I have found a couple of dead fleas on the white kitty but I don't believe that there was a huge infestation.
My husband is horrified that his darling baby had fleas and he wants to use Frountline every month, like for forever...is that necessary? It's a chemical and I would rather not , but I do consider it to be the lesser of two evils.
So, what's your protocol for fleas?

Frontline is good for about 3 months, do not let him dose the cat every month. It is not benign, it is an insecticide and I couldn't swear that some of my pets that have died of cancer didn't get it from regular applications of Frontline etc.

It takes a couple/few days for the fleas to die and the bites to stop itching after the application, be patient. Should work.

Oh, it works that's for sure...he picks over her like a mother monkey and he has only come up with 2 dead ones and strangely, no flea dirt to be found. And the cats were not scratching at all.

So, like EVERY 3 months, even if we don't see another flea?
They are indoor cats, don't ever go outside except for the open air patio at the center of our house. They do sit at the screen door in front of the house where a flea could transfer from another animal to them , I guess. We have had 2 mice in the last couple of years...I guess they have fleas, huh?

I am wary of Frontline too, My cat that I brought here from the U.S. got a tumor in his stomach and died 2 years after arriving, and my dog died of a mystery illness shortly after that.. They had both lived in a farm/stable environment and got frontline regularly...I am also a firm believer in bottled water for my cats...if tap water isn't good enough for us, it's not good enough for them.

The guy at the cow store in Chapala told him to put it on every month but we won't do it that way (and I'll buy it at the shelter next time).

I don't use it repeatedly on my animals either. Most of my cats are ferrel. Once in awhile my dog's get fleas we just bathe them dawn or Palmolive . We only use frontline or comfortis for bad infestations and also spray animal areas as needed.

I have been told the rainy season and flea season overlap. I usually only put one FrontLine application on the cat per year. Since one of the dogs is super allergic to fleas, he gets meds all year round.

I have always used boric acid powder to control fleas. It's a natural, mild antiseptic that is often found in eyewash solution. It will not harm your pets even if they lick it. It's available at pharmacies and hardware stores. Just spread a fine line of the powder in the corners of your house, where the floors meet the walls. It not only kills fleas, but roaches and most crawling insects.

Would Frontline or Boric Acid get rid of John?