I must be lucky. I perform my research and go visit any of three bike shops near me. Then I ask a few more questions and all is said and done. Sometimes I do the work. Sometimes they do the work. Neither of the three shops has steered me wrong.... I do enough of that on my own.
It helps that I generally know what I want before I walk through the door.
Even performance has not caused me issues. However, I tend to only purchase items there.
The other three shops are staffed with wrenches I trust.