On a full wind, it should run somewhere around 40 hours before it runs completely down and stops.
If it's worn each day, and the wearer is reasonably active, the natural motion of the wearer's wrist should keep it charged up sufficiently that it shouldn't run down at night, and as long as it's worn each day, it should keep going indefinitely.
If the wearer has a somewhat sedentary activity level, it might need to be re-wound by hand every couple of days or so to keep it from stopping.
Hope you enjoy the DJ - it's a classic!
Steve