My favourite is "Stronghold"  It's a spot on the neck thingie that takes
care of worms, skin parasites and ear mites all in one go.  It's ideal for
my two who can be shy about being handled, but unfortunately, up to now, I
can only get it from the vet - which means it's at least double the real
price.
I use it "just in case."  KFC & BF have never shown any signs of skin
parasites like fleas, but Kitty once had ear mites, years ago now, when she
was just coming into the house after her feral years.  As for worms - there
is a risk as Boyfie catches wild food and Kitty eats it when he presents it
to her.
He *never* eats his catch himself.  After the rat scenario last week I hope
he'll ease up on prey catching for a while.
It was sort of funny in a way.  I suspect he was around the woodheap looking
for mice or very young rats, which he is able to deal with.  He probably saw
a movement and pounced and found quite a large rat in his mouth.  He ran for
the house with it.  He quickly realised he'd made a big mistake..
He is such a gentlecat that his killing bite is not up to sorting big rats
out.  I hope he learns that soon.
What a clever rat that was, pretending to be dead as the cats sat over it.
We underestimate their intelligence.

Tweed

It's a step in the right direction. I wonder why it's only the Frontline
'Spot-on' that's going OTC and not the spray?