I think it's important to keed your pet healthy. Each time I adopted a cat, my vet gives the new cat the medication for that. Because my cats are indoor cats, they get the treatment only one time.
But even if the cats are indoor cats, they have to be vaccinated every year for rabies because of the law where I live. It's because some "wild" animals might get into your house and contaminate the cats or dogs.... animals like squirels (we had one at one time), bats, raccoons, skunks, etc.
The bottom line is that if I choose to own a cat (*), I want to take good care of it. The cats always have been part of our family!
(*) I know..... I don't own the cats..... the cats own me ;-)