I have 5 cats and all cats go in for an annual vet visit and vaccinations. Unfortunately with Ripley's kidney failure and constant UTIs he has to go in more frequently.
I can tell you in comparison my dog Disney costs much more in vet care and prevention than Ripley has because she had to have heartworm check and pills, fecal exams, flea and tick medication and her vaccinations cost more. She also had rotten teeth and had to have a dental about every two year (more frequently towards the end) plus she had allergies that would act up in spring and fall. Since my cats do not go outside they don't require near as much stuff as she did. I still miss her though and I'd do it all over again (hopefully I will someday soon). :(