While the definition of "puppyhood" can vary slightly depending on breed and size, most dogs reach adulthood around 1 to 2 years old.
Here's a general guideline:
* Small breeds: May reach adulthood around 1 year old.
* Medium breeds: Usually become adults around 1.5 to 2 years old.
* Large breeds: Can take up to 2 to 3 years to fully mature.
However, even after reaching adulthood, dogs continue to learn and develop throughout their lives.