It would be nice if animals lived for a lot longer than they do, and dogs especially have relatively short lives. Most dog varieties have a life expectancy of 15 years, while the average life expectancy of a human being is 75 years.
Dogs will usually reach maturity after one year. Humans live five times longer than dogs, and one dog year is equivalent to seven human years. Year one counts as one year, and then every year after that is equal to seven years. It all depends on several different variables.
It is the type of breed, size, gender, nutrition, and living environments for dogs. Most of the time, it is the overall health of the person that determines life expectancy for humans. Small dog breeds also tend to live longer than large breeds. Human beings depend on fitness and nutrition to maintain good health.