Elmer, I saw your other post on your option trading with Schwab. One thing we do differently is that I always trade at the market price rather than a limit price. I used to try to use limit pricing, but I found that I can't consistantly outguess the market and that trades go faster when I just choose market price. Overall, that seems to work for me.
Maybe their computer system shops the exchanges better when market price is specified.
Market Data 
Markets 
AI
