I'm relatively unfond of the term tune-up. Service should be appropriate to the needs of the rider and bike and should be charged fairly relative to the shop's labor rate. Any service package should be well defined for both mechanic and customer. In my experience, typically a "tune-up" without any other qualification means adjusting most everything on the bike and a basic, surface level cleaning. Typically I'll:
-Remove wheels, wipe them down, quick lateral true and and correct and serious spoke tension problems, adjust adjustable hubs.
-Wipe frame down and inspect.
-Adjust HS, BB preload if needed.
-Check der hanger alignment and correct of necessary.
-Wipe/lube chain.
-Adjust derailleurs.
-Adjust brakes.
This is probably about 45-60 minutes of efficient work. I like having service packages that are basically just dt/brake adjustments (20-30 min), tuneup+new cables, +bleed, etc.