We don't have visual flight tracks here as far as I'm aware so maybe I'm thinking it is a much more exotic thing than it is in your part of the world.
Personally I think you should know everything you're likely to come up against regularly, and be able to quickly reference anything that is rare.
Edit: I take that back, we do have visual tracks (and I've flown approaches that use them) for some reason I thought you were talking about enroute charts, carry on
. And I agree, you should know almost everything that comes up on an approach chart.