The average lifespan of common small dog breeds such as mini poodles, toy poodles, and mini dachshunds is between 12 and 16 years old. The average lifespan of large dogs is usually between 9 and 12 years. The lifespan of medium-sized dogs is somewhere in between, with the average lifespan being about 12 to 15 years.

However, some dogs can live longer, and some individuals can even live beyond 20 years, but this is not the case. Unusual. Conversely, some dogs may have shorter lifespans due to disease or genetic factors.