Number of yrs. to reach the finished line?

Depends on your bankroll. If you have a butler to move your speakers just right for the sweet spot, it doesn't take long.

How do you know when you've reached the finish line? Before I discovered the "high end", I thought my "midfi" was hot stuff. It wasn't until I wandered into a "high end emporium" that I made a startling discovery. Now that those places are almost gone, where can you compare what you think is the finish line.

After we moved, I discovered how much the room means. The new room has a vaulted ceiling and the speakers are not close to the front wall. If you have speakers that work well close to the front wall, keep them, and experiment with amp and pre.