One of the big enhancement to 2013 is a revamp of the stairs. They have now made the stairs component based stairs. this gives us a little more control of the stairs. The strings and the landings become separate objects from the stairs, much like railing are separate. Speaking of railings they have enhanced them as well. They have now put built in extensions to a rail. To add the extensions you need to remember to tab to the individual rail that you want to extend. Because this is such a new approach to the stairs within the Autodesk Wiki Autodesk has 10 videos about stairs. The folks over at Designreform.net have also put together a 16 minute video on the stairs.