The short answer for a very small dog
Write down the exact weight, the state of the teeth, the knee check, the heart and breathing comments, and the next due date after every vet visit for a Chihuahua. Almost everything about this breed's record-keeping comes back to scale: a Chihuahua is small enough that changes other owners would never notice, a loose tooth, a slightly wobbly kneecap, a few ounces gained, are genuine health information. The visit note is where those small findings stop being things you half-remember and become a timeline the vet can act on.
Teeth, knees and ounces: the Chihuahua entries that matter
The dental entry leads for a Chihuahua because crowded teeth in a tiny jaw trap plaque in places a chew cannot reach, and vets track which teeth are loosening or building tartar visit by visit. Record which teeth were mentioned and whether a cleaning was advised or booked. Next, the knees: write down what the vet felt when checking whether the kneecaps track steadily, in the vet's own wording, because comparing that phrase across years is how a mild finding gets watched properly. Then the weight, written exactly as the scale showed it. On a Chihuahua, rounding to the nearest pound can hide the entire change, so ounces count. Add any comment about coughing or the windpipe, and any heart sound the vet wants to recheck.
How to capture the visit while it is still fresh
Make the note before you leave the car park, while your Chihuahua is still tucked against you and the appointment is minutes old. Start with why you booked it and the vet's bottom-line verdict. Then list the findings in exam order: mouth, heart, knees, coat, and the weight as read. Anything you were told to do at home goes in as an instruction with a timeframe, such as when to recheck a tooth or how the vet wants feeding adjusted for the weight trend. Close the note with every date the visit created: results expected, boosters due, and the recheck the vet named. If the vet used a phrase you did not fully understand, write the phrase down anyway and ask about it next time; an exact phrase in the record is worth more than a confident guess.
What Chihuahua owners most often forget to record
Owners of Chihuahuas most often forget the everyday observations the vet actually asked about. If the vet asked whether the coughing after excitement has changed, your answer belongs in the note alongside the date you gave it, because next year's comparison depends on it. Record, too, any wobble, skip or bunny-hop you mentioned in passing, any tooth that came out at home, and any appetite change in a puppy or a senior, since small dogs have less reserve and the vet weighs those details heavily. Also note who examined your dog if you see a multi-vet practice; continuity of phrasing across notes is easier to judge when you know whose wording you are comparing.
When a note should become a phone call
A Chihuahua's record earns its keep when it tells you a small change has stopped being small. Call the clinic if your notes show the weight falling across two visits without a feeding change, if the knee comment worsens from one check to the next, or if a tooth the vet was watching starts stopping your dog from eating on one side. Breathing difficulty, repeated fainting or a puppy who will not eat is an urgent call, never a wait-and-see note. With each visit filed in your KinsLe Pet Passport, the whole run of weights, dental notes and knee checks stays in one place, ready to hand to an emergency clinic that has never met your tiny dog.