I take them to the magnificent Dr. Rossi within a week of getting them for general inspection, fecal check, and deworming.

Then after that, all my pets except the hamsters, rats, turtles, and fish get a yearly visit in January (my first ever pet dog's birthday - the rest of the pets just follow the schedule so it's easy for me to remember). Of course, if something is the matter, I take them then as well.