How do I know what is the best prevention for my cat?

You should definitely talk with your veterinarian about the best prevention for your cat. There are over-the-counter options and prescription options. Prescription options are always the better choice. Over-the-counter options can be toxic to cats, and even those labeled for cats can sometimes cause problems. Prescription options are also more effective, as many over-the-counter options have been on the market for a long time and are no longer effective, as fleas and ticks have grown resistant to them.