If you're in any kind of chain, you can bet it's pretty standardized and in the neighborhood of 1.25 oz. for spirits. Independent places are where it varies. Even in some upscale chain places that employ real bartenders you will see free pours and generous servings of straight spirits.
But one thing I hardly ever see anymore that used to be routine in real drinking bars is the practice of comping every third or fourth round. I miss that.