Monocle wrote on 12/21/16 at 13:52:44:
I'm just wondering if anyone else has had to make a similar decision about what openings they want to be playing long term while still trying to improve after the age of 35
I certainly agree with other posters that you should find something that you like, and also, something that is good. I tend to migrate between looking at, and playing, about three lines for black and maybe a couple for white.
For example, I first studied and played the King's Indian Defense, then the Nimzo, finally double queen pawn. I still check things out in the KID, and I may return to the Nimzo. I suspect the Nimzo is best, but I'm having fun with double-queen pawn right now.
Sometimes I run into a brick wall. At one time or another I think I have looked at everything in the fianchetto KID. The only line I believe to be satisfactory is ...c6, ...d5. So far, I have been unable to develop any enthusiasm for a KID that is also an exchange Slav! I keep looking at the KID, but with reduced frequency.
As white, I played the Open Sicilian for decades. I then played the Closed Sicilian for a couple of years. Now I play the Rosolimo against 2...Nc6. I need to tune up the Open lines that start with 2...d6 and 2...e6. Even the Rosolimo may turn out to be a temporary diversion, like the Closed Sicilian.
After playing the Ruy Lopez for decades, I've had fun with primitive openings that I never played as a youngster: the Evans and Scotch Gambits. However, I reserve the right to return to the Ruy.
I do not consider an opening repertoire choice to be irrevocable. Granted my approach has not been "efficient" or "optimal" from a particular perspective. I just adopt a different perspective.