This mostly has to do with cats, since I was going to mention the abscess. The abscess is an infection under a cat's skin, usually from another cat if your cat is an outdoor animal.

It is always most ideal to take a cat to the veterinarian, and if there is any chance of this, please do it. However, considering how common cat bites are, if you don't have enough money to treat their wound, if the wound is squeezed out, and gently disinfected by flushing it out, it will heal just fine. If you do choose to do this, wear gloves, as the infection may be human-transmittable. If nothing is done, the infection by anaerobic bacteria will spread and possibly kill the cat. Anaerobic bacteria are bacteria that survive without air, and they are some of the most dangerous bacteria to possibly infect an animal.

I would also like to note that engraving your phone number or name on dog tags is one of the most useful things you can do for identifying your dog, since it allows easy return of the animal, especially a cell-phone number.

Keep your dog's nails clipped. It prevents them from becoming ingrown. Also, please either clean their teeth, or take them to get dentals regularly, since dogs get terrible tartar and tooth decay from eating dogfood, causing tooth loss or infection.

If you have cats, please please keep them indoors. I have been working at a clinic, and a lot of the cats that come in have horrible injuries from animals like dogs or coyotes, or are infected with the viruses Feline Leukemia and FIV(similar to aids in humans), which are usually passed through cat fights. Even vaccinated animals are not immune to getting these viruses, and they are much safer than they are in outdoor environments.

Lastly, if you are going to buy an animal, set aside the money to take care of it. The price of owning an animal is massively more than the price you will pay initially buy it, as no matter how careful you are, something will happen to your pet.

I hope all this helps.