The average lifespan of a dog varies significantly based on factors such as breed, size, and overall health. Smaller breeds, like Chihuahuas and Dachshunds, often live longer, typically ranging from 12 to 16 years. In contrast, larger breeds, such as Great Danes and Saint Bernards, usually have shorter lifespans, averaging around 7 to 10 years. Genetics, diet, exercise, and veterinary care also play crucial roles in a dog's longevity. Regular check-ups and a balanced diet can help prevent health issues, contributing to a longer, healthier life. Understanding these factors can assist owners in providing the best care for their pets.