Duncan being our first dog (first Border Collie) and only dog for several years got a lot of our attention and time. We had him for 4-5 years before we started with sheep herding. We learned several key Border Collie owner lessons:
-Border Collies can play fetch indefinitely (at least longer than I am willing to throw)
-Playing fetch has short term benefits for the owner's desire for a tired Border Collie; the dog only gets more fit
-Throwing a toy (or anything, example stick, rock, glove, pinecone, etc) makes that toy a "throw toy" and no longer a self entertaining toy
-Working their brain provides the calm, resting Border Collie the weary owner desires
We discovered that playing hide n seek with one of Duncan's toys was a great way to wear him out. We would put him in a stay (sit or down). Show him the toy and then place the toy out of his sight. Come back to him and then tell him to go find it. As he got better at this game we would leave him in a place where he couldn't see what room we went into, he only knew we left the room he was in. He learned to scent for the toy, following the odor trail through the house as we went from him to the hiding location. This meant we had to get more creative; I started dragging the toy along the floor into other rooms before hiding the toy. He then scented and also had to visually search.
Herding livestock does both (work the body and work the brain) which is why this breed needs so much. I can take a very physically fit young Border Collie (able to play fetch for hrs) and exhaust them in 5min working sheep because of the mental focus that is involved with this activity.