My dog constantly surprises me and he's only 3.5 years old.
The first year I had him as a puppy, he could smell/hear (?) his best neighborhood buddy walking multiple buildings away from our apartment while the windows were closed. He'd run to the door and start crying and as soon as we got outside he knew the right path. And his friend hadn't even walked by our building yet, so it's not like there was a trail to sniff other than whatever may have been carried by breeze.
The first year I had him as a puppy, he could smell/hear (?) his best neighborhood buddy walking multiple buildings away from our apartment while the windows were closed. He'd run to the door and start crying and as soon as we got outside he knew the right path. And his friend hadn't even walked by our building yet, so it's not like there was a trail to sniff other than whatever may have been carried by breeze.
Dogs are incredibly smart.