It really frustrates me as a vet when people claim that dental work for animals is some kind of money making con. Vets don’t recommend beneficial procedures to animals to make money, we do it because we want to help. How many people manage to live into their 60s/70s/80s, never brush their teeth and never need a filling or extraction or get painful root infections?
Dentistry for animals can in some ways mirror humans, that there are some people who do bog standard brushing, never see the hygienist and only need the dentist every 10 years, others who have to work really hard to look after their teeth and still need lots of work doing. Animals can be the same, it can be down to diet, lifestyle, genetics and sometimes carrier status for viral diseases.
Dental hygiene benefits all patients, but as proper dental cleaning requires an anaesthetic, there is a balance to be made against reasonable frequency/timing to get the maximum benefit, balanced against age and other medical conditions which may make anaesthesia more risky, and cost to the client. This is often where advice about “when to dental” is subjective and can vary from vet to vet.
Some cats will form tartar that can just be chipped off and their gingivitis will improve, others can have infected teeth, exposed roots, inflammatory gingivitis or enamel erosion at the gumline which is extremely painful where the nerve is exposed.
Extracting tiny roots from a relatively fine and flimsy jaw is technically difficult and requires patience and special equipment/xrays to do properly. A lot of vets don’t enjoy dentistry but appreciate that it can be one of the most significant parts of our job for improving quality of life for animals.
in regard to OPs question. Ask for a pre dental check and an estimate for the dentistry they recommend. Are x-rays included as standard? is there a cap on time and could the dental extend into a second stage if a lot of extractions were needed? Costs can easily vary between £500-1000 depending on what is needed. There are dedicated cat clinics and dentistry centres who may be worth looking into for maximum dental expertise.