* Martin finally arrived—disheveled and drunk.
* During her entire life—99 years—Anna never tasted alcohol or ate pork.
* His autobiography—if you choose to glorify it with that word—came out in print in 2011.
* The White Sox have a good chance to win the pennant—if they can beat the Orioles.
The dash seems to have become the most overused mark of punctuation. Use it sparingly and it's effective; use it too often and it makes the writing trite or overwritten.
Consider this example of overuse: After we looked for poor Mitsie—for at least an hour—we found her—shivering in the rain. We carried her into the house—really the back porch—and wrapped her in a thick, woolen blanket—an older one that we could throw away.
The dash interrupts a thought
for emphasis. I'll use it carefully.