Obviously it's a big no-no to pick up a pipe for sale and wrap your lips around it for a test draw. So are there any ways to evaluate whether or not a pipe will smoke well just by looking at it or holding it? Maybe by taking off the stem and looking at the airway? I'm thinking about the Chicago Pipe Show coming up in less than weeks, where I'll get to admire and thousands of pipes for sale that could potentially be mine (although budget constraints will surely narrow my prospects). How do you evaluate quality in hand?