@Turquoisesol yes 6 months. And I know what you mean as naively we didn't do much research into breed, breeders etc (I only realised you're supposed to do that after we got a puppy and I joined a puppy forum
) So I was the same as you initially omg what have we done getting a collie because everyone kept saying how high maintenance they are.
So I'm not an expert by any stretch of the imagination but these are some of the things we do in the hopes that we satisfy his natural instincts and tire him out mentally and physically...
Lots of people have said to give them a job so we're in the process of teaching him to tidy up 
Also we try to make him work hard for his food so try to feed him in different ways every day - rolling kibble in a towel, putting it in all the recycling, scattering around, put it in a bix box and then bury it with all his toys. Theres a Facebook group called Canine Enrichment which has really good ideas.
We kick balls to him in the garden and once he's caught one we kick another one to him in another direction. There's a game called sheepball you can teach them which is similar but more complicated. We also blow bubbles which he loves and the kids can do (but you have to get them to blow them low then stand up quickly so he doesn't accidentally snap their face!) also we throw kibble to him a piece at a time and he gets in his herding position and pounces on it then goes back to lie in wait for the next piece.
We did buy him a boomer ball but he's not interested in that.
He does have lots of energy and to begin with I regularly questioned if we'd made a mistake. He always seemed to need entertaining. But these last few weeks he's really chilled out. He gets 1 or 2 walks a day mostly off lead chasing a ball and running with the kids, and we play in the garden a bit and he likes to go in the garden and have a sniff about on his own, and other than that he is very calm and sleeps a lot.
The onle breed-specific downside is that he wants to herd cars which is a PITA 
Like I said in a pp he does prefer us to be together and will try to round us up on walks but it doesn't bother us and actually it's quite nice to know he's looking out for the kids. Plus I think it keeps him close to us because he wants to make sure we're all together. Our walks with him are the highlight of my day (unless we're walking along a road of course!)
Sorry that was so long and I'm not sure how helpful any of it was. I'm still learning!