Interesting premise: A set up performed by a professional technician who has performed the task literally thousands of times cannot possibly “tweak it to personal perfection for you.” The implication is that someone with limited experience and tooling will be able to do a better job than a professional working under ideal conditions because the amateurs are working on their own gear. Try that argument at a local auto repair shop or professional remodeling contractor sometime.
It reminds one of the Marlon Brando line in Apocalypse Now: "The horror...the horror."
By asking, and by watching the person play and listening.
The determining factor in this process is communication. As long as the customer communicates how they want the end their guitar set up the professional tech will be able to produce the desired results. The communication can be verbal or the tech can observe how the owner plays their guitar. In most, if not all cases, the finished product will be superior to the amateur attempt.
So how do these myths get started?
When problems arise they are generally one of several kinds. The first is that the request is not specific. As an example, the customer requests that the action be as low as possible without buzzing. How low is low? What is acceptable buzz? What is expected? Who knows? There is a total breakdown in communication. That leads to the second kind of problem.
This problem arises when the guitar is in need of advanced service. For example, the customer requests that the strings be lowered as above but uneven fret wear prevents this. Many customers will accuse the tech of trying to gouge for extra services because the simply do not understand how a properly manufactured guitar could have uneven frets. Or that the frets on a new and expensive guitar are not even. Or that they have worn the frets and service is needed. Or that frets can be serviced, period.
The third kind of problem occurs when the customer demands that the tech suspend the laws of physics as are observed on this planet. For one example, the customer demands super low action with no buzz of any kind being acceptable, and then strum very hard thereby causing huge string deflection that causes the unacceptable buzz.
There are more situations that arise than this. But that’s another thread for another forum.
