This is By Far the better commercial product.  Vets use products exactly like this - and it has been proven to work and is safe as long as the user knows what they're doing.  The only time to use this product is when there is a problem.  I would not ever use any sort of drug unless the need is called for.  The idea of using these types of drugs as a regiment is silly.  If you have a flea problem on a constant basis - you need professional exterminators to handle your living conditions.  But if, by chance your kitten comes into contact with fleas (like a neighbor bringing them in or getting them at the Vet) this product works great.  Use the first 'squeezer' and see if the pests are still around after a month.  If so - you've got the problem, not the kitten.  If not - don't put the animal through the drug any further than needed.  It's just like any other form of chemo-therapy.  And I know all about that...