Dogs generally live about 12 to 15 years. Large dogs have a shorter lifespan, while small dogs have a longer lifespan. Some dogs can even live about 20 years. The lifespan of a dog will also be affected by the breeding environment and its own body constitution. If the owner takes good care of the dog, lets the dog live indoors, and takes the dog for appropriate exercise, the dog's lifespan will be longer; but if the dog lives outdoors , if not well cared for, life will be shorter.