What do you wish you knew before?

My wife and I are going to look at a 5 month old puppy today. He is a mutt, but very much red healer as the predominant breed.

We’ve researched the breed a lot, and I know that we can handle an ACD. We have both had dogs our entire lives, and we currently have a 12 year old beagle x blue tick mutt that we adopted 10 years ago. We are an active family, hiking, boating, camping etc., and I run ultramarathons, so I think we can handle the physical and mental energy demands an ACD comes with (at least as well as anyone not living on an active cattle ranch can).

But what do you wish you knew before you brought an ACD home? What would have made your lives easier, or even caused you to change your mind entirely, had you known it before?