When a dog licks the tongue passes over this bulb for instantaneous odor sampling. Imagine a 100-yard dash in 7.14 seconds. Dogs are extremely smart. They can learn up to 200 verbal commands and have a precision memory. Although some experts argue this it is probably more a factor of reading body language.
Canines use body language as a primary means of communication besides smell.
They transmit rank, social status, dominance and defense through body carry, ear set and tail position. Like anything, if you don't take care of it then it won't last. Barring any severe physical injuries or illness a dog can work the street comfortably until they are 7-10 years old. That's about 65 in human years.