Originally Posted by
Lawrence08648
Your mechanic is incompetent and it should never have happened. I tighten all headsets using a torque wrench.
I'd like to see you use a torque wrench on a threaded headset

Still, I'm surprised you could get consistent results using this method even on threadless headsets, as most that I work on are neglected and damaged, which brings us to...
Originally Posted by
Kimmo
Unless the headset has issues of some sort. Then it's usually a matter of leaving it overtight until you get a new headset.
This. If your headset is damaged and replacing the grease and balls does not cure it, there's really nothing you can do. So then the headset has to be tightened quite a bit to remove slop, to the point where it's stiff has tight spots.
But unless the mechanic actually rebuilt the headset first, then it shouldn't have been tightened like that. And even then, only if it's damaged beyond proper adjustment.