I keep my pets on the same madical rutine as my self If there is nothingg wrong we dont see the Dr. That being said even If we think there is a problem we call right away and ask if they should be brought in. When I have brought them in they have been in perfect health. If your worried about your pets health I sujest you Spend time with them and put aside time daily for brushing and playing.
Big Dr bills wont help your pet or your self. If you are paying attention to them you should see signs if there is somthing wrong. First shots are important after that I would play it by ear.
On the other hand if you are The DR typ they do have pet health insurence.