I think the best I've played was in my 30's, when I was playing alot. Now I'm back to playing 3 or 4 months a year, and mostly only 3 or 4 times in a month. It used to be if I ran out now and then from a open shot I was happy. Now I'm aggravated when I don't run out, because I expect to get out.
To me the biggest difference between a low b (me) and a A player is defensive shots and when they are played. I'm probably more likely to sell out if I get out of line, than I am to play a good safety.
Seems the better you get, the more you realize how much you have to improve. If you want to be a good player, play the best competition you can, watch the approach to defense, to run outs, even to the break.
And wish I played one pocket, because its a game that helps in almost every other game. Lack of 9ft tables in my area makes it a rare game.