Last place I worked had a 'Basic Tune up' which was adjustments and a bit of cleaning, and a 'Full Tune Up' in which most of the drivetrain was stripped from the bike and cleaned in a parts washer.
Basic Tune up probably took between 20 and 40 minutes, depending on the bike's condition; 'full' tune up was 1 hour to 1.5 hours. Sometimes for the full tune up, if parts were heavily covered in schmutz, the bike would be stripped and some parts would be left to soak in degreaser and another bike was started.