I emailed my old instructor to ask if he'd be interested in helping me with a very specific issue (getting my hips forward on the downswing). He asked if I was finishing in balance with my weight forward. I told him I was. Then he asked why, if I was finishing in balance with my weight forward, would I care if my hips slid forward (for the record, I happen to agree with him on finishing in balance). I told him that I believed by getting my hips forward, it would allow for an inside to out swing path, make it easier to get more shaft lean to deloft the club, and maybe improve lag. After a couple of emails back and forth, it became apparent that he didn't want to waste his time with a lesson and I decided not to continue the pissing contest with a PGA pro who plays near scratch golf.
I may be completely wrong on why the hips should move forward, but based on every slow motion video of any pro I can find, it seems like an important key (or move, component, part, piece - I'm now gun shy on using an incorrect term). It's why I keep working at it even though it's hard and my contact is already much better than ever. And here's an instructor who doesn't see it as important even though this probably occurs in his swing.
There are PGA pros on youtube who don't subscribe to keeping the head relatively still, believe that you should restrict the hips in the backswing, tell us the only way to achieve distance is for the club to be at parallel at the top of the backswing, and claim that the initial flight of the ball will follow your swing path and not the club face. All of these folks are better at golf than I'll ever be and it would be stupid for a 30+HC to argue any point with them. But I can choose not to listen.
I simply decided to try and develop a swing that includes these keys. What I call it or how I try to learn it may not be correct but at least there's a plan - which is more than I had last year.