Some Pet Insurance premiums do increase with the age of the pet.
As the pet gets older they are risk at developing health issues which need vet care so the pet insurance companies raise your monthly or yearly pet insurance payment.
A few other pet insurance companies such as Healthy Paws and Trupanion do not increase pet insurance premiums no matter the age of the pet.
However pet insurance only covers health issues that occur with your pet after the pet insurance has been in effect for at least 1 year or more.
So you cannot just get pet insurance and have it cover a pre existing condition.
In my opinion pet insurance is not worth it because with most pet insurance you really have to pay out of pocket for the vet visit as well as the procedure and then they reimburse you.
So for example if your pet required a $1,000.00 or more in care or needed surgery then you would have to pay that out of pocket and if you didn't have that then the pet insurance would not be helpful anyway.
Some vets may allow a payment plan though which is what I did when my dog needed surgery to remove a ball that he swallowed.
I was able to pay them $100.00 per month until I paid off the balance which was $1,500.00 for the surgery and other stuff.
Not all vets will allow a payment plan but some do especially for emergency procedures.