Like other medical professionals, vets are regulated and must typically attend a post-secondary institution, obtain a degree and be listed as a member in good standing with a state veterinary association to open a practice. A "vet" who practices without a license can face stiff fines at both the municipal and state level if caught. Vets operate out of clinics and take appointments for animal visits. Most major cities have at least one emergency clinic which operates 24 hours a day, seven days a week and takes pets on a first-come, first-serve basis.
Much of what vets do falls into the category of preventative medicine. Pet owners make regular appointments to have a checkup for their dog or cat, which will include things like taking its weight, checking its teeth, and possibly testing its urine. Vets also perform immunizations for a fee. The immunizations -- necessary if you ever need to take your pet to a kennel or have a professional pet sitter come to your home -- include shots for diseases like rabies, distemper, kennel cough and feline leukemia.
If your pet has a specific ailment, your local veterinarian can also help. Urinary tract infections, for example, are common in dogs who swim in local lakes or rivers. Vets can both identify the infection and prescribe antibiotics to cure it. They can also schedule and perform certain surgeries such as spaying and neutering, which prevent your pet from accidentally getting pregnant or getting another pet pregnant. In female animals, spaying involves the removal of the ovaries and uterus; in males, neutering is the removal of the testes.