The $0.25 trigger job does nothing to alter the feel of the trigger. It is nothing more than a psychological placebo made incredibly popular by it's pretty much free cost and incredible easy DIY qualities. People want a lighter or smoother trigger, and people love cheap/free. The concept behind it makes perfect sense, like in an engine we believe polishing components will enable them to operate more smoothly thus giving us the effect we so desire.
While this is true in engines (for the most part) it is not true inside of a Glock in regards to the trigger components. The trigger feel is not a result of the finish on the connector or any of the other parts, but rather is a result of the desgin. The feel comes from the stress breaking point of the contact points and such of the parts, not the mating surfaces. Anyone with the proper instruments to measure the trigger can tell you it does nothing. Now if you polish a brand new Glock or a filthy old as dirt Glock you may notice something real. This is not by altering any kind of design or by the concept itself, but rather by the need for a break in period and the need for a good cleaning, respectively.
Continuing on with our engine comparison, in the early 90's dirt bike sports saw a mjor boost. People were desperate to squeeze out any additional power they could and spend as little as possible. Shops across the country started abusing the terminology "powerband" (meaning of course the point across which an engine makes the most power) as if it were an actual part. They would sell red, yellow, blue, etc powerbands to customers. This was nothing more than a literal colored band placed somewhere on the motor or the bike depending on their story, and they would tell customers of it's performance effects on the engine. These same people would bet their life that the bike almost doubled in power. Another example of psychological placebo.
It's nothing more than basic psychology and a total waste of any time invested into it.
