There is no birthday on which a pet becomes old. The American Animal Hospital Association says so in as many words: "there is no specific age for senior status." For dogs it counts the last quarter of the expected lifespan as the senior years, which starts around 6 or 7 for a Great Dane and past 11 for a Chihuahua. For cats it is anything over 10. What changes at that point is not the animal so much as the schedule: two visits a year instead of one, and a set of tests that catch the slow diseases while they are still cheap to manage.
AAHA's canine life stage guideline says senior dogs "should have at least semiannual exams," and the feline one says "senior cats should be seen at least every 6 months and more frequently for those with chronic conditions." The reason is arithmetic. A year is a long time in a life of twelve, and the things that go wrong in old animals, kidneys, thyroid, joints, teeth, blood pressure, all move slowly enough to catch between visits and fast enough that a whole year is too long.
AAHA's 2023 senior care guideline lists the tests and how often. Short version below; the full table is on their site, linked at the bottom.
| Test | What it looks for | Dogs | Cats |
|---|---|---|---|
| Complete blood count | Anemia, infection, some cancers | Every 6 to 12 months | Every 6 to 12 months |
| Chemistry panel | Kidneys, liver, blood sugar, protein, electrolytes; SDMA for early kidney loss | Every 6 to 12 months | Every 6 to 12 months |
| Urinalysis | How well the kidneys concentrate urine, protein, sugar, blood, infection | Every 6 to 12 months | Every 6 to 12 months |
| Blood pressure | High pressure damages eyes, kidneys and brain quietly | Recommended every year | Strongly recommended every year; every 6 to 12 months in healthy old cats |
| Thyroid (T4) | Underactive in dogs, overactive in cats | Recommended every year | Strongly recommended every year |
| Fecal test | Worms and protozoa | 1 to 4 times a year, depending on prevention and lifestyle | 1 to 2 times a year |
| Heartworm test | Every year | Per the American Heartworm Society guideline | |
| FeLV and FIV | — | Based on the cat's risk |
Imaging (x-rays, ultrasound) is added when the exam or the bloodwork points somewhere. So is a urine protein test if protein shows up in the urinalysis.
National averages from the 2025 to 2026 Synchrony cost study for CareCredit. Your clinic's price will differ; the vet costs page explains what kind of number each of these is.
| Item | Dog | Cat |
|---|---|---|
| Geriatric screening (bundled) | $181 | $182 |
| Chemistry panel | $164 | $144 |
| Complete blood count | $104 | — |
| Thyroid test | $125 | — |
| Urinalysis | — | $54 |
| Blood pressure | $36 | $35 |
| Fecal exam | $58 | $29 |
| X-rays, two to three views | $172 | $158 |
| Dental cleaning | $379 | $395 |
A senior visit with the exam and the bundled screen runs a few hundred dollars, twice a year. Wellness plans bundle roughly this set; whether one pays off depends on whether you would have done the tests anyway.
AAHA: "Clients often perceive changes in their geriatric pets as normal aging when it may be the result of clinical chronic pain." Slower on stairs, hesitating before the jump, sleeping more, a shorter walk, grumpiness when touched. Osteoarthritis is treatable, and untreated it shortens the good years. Say what you have noticed; the vet has pain checklists for exactly this.
AAHA puts age-related cognitive impairment at "14 to 22.5% of dogs older than 8 yr." The signs go by the acronym DISHAA: disorientation, changes in social interaction, sleep-wake cycle changes, house-training lost, activity changes, anxiety. Cats show it too, often as more meowing and more clinginess. There are diets and drugs; AAHA says the diets work best "combined with environmental enrichment (exercise, new toys, cognitive games, tasks, agility)."
Old cats lose muscle: "up to 33% loss in cats from 10 to 15 yr." AAHA says senior pets, "particularly cats, may need up to 50% more protein to improve or slow muscle loss." Dogs tend to lose muscle and gain fat. A body condition score of 4.5 to 5 out of 9 in dogs, and up to 6 in cats, is associated with living longer. Weigh them monthly; the trend matters, not the number.
AAHA: "Examination of the oral cavity should be done at every veterinary visit." Periodontal disease is more common in small and old dogs, and "oral tumors are more common in older dogs and cats." The dental cleaning needs anesthesia, and old animals need extra care under it, which is another reason the bloodwork comes first.
My Pet prints all of this on one sheet for the desk.
AAHA warns that "most QOL scales found online are not currently validated" and suggests a validated one, used with the vet, so the picture is not only your memory of a good week. When the question is bigger than a checkup, when is it time? is the page for it, and it does not sell anything.
Slower on the stairs can be pain. The signs in a dog, with a checklist to print for the vet: How do I know if my dog is in pain?
The signs in a cat, with the five things vets read in a cat's face: How do I know if my cat is in pain?
What each test in the checkup looks for, how to prepare for it and what a result can and cannot tell you is on four pages. The first one is: Why does the vet want a stool sample?
What the kidney values in a senior cat's blood and urine tests mean, stage by stage, is on a page of its own: What does chronic kidney disease mean for my cat?