Like people, dogs additionally show a decrease in strength the older they get. The most popular theory that compares dogs and humans uses this equation: Dog years multiplied by seven years is equal to human years. However, this straightforward equation is only a rough gauge. A more exact correlation of human versus dog age considers the canine's breed and size. Smaller pooches age slower and have longer life expectancies. At the same time, bigger dogs age rapidly and have more limited life spans. Additionally, particular breeds have more years in them than others.