We all approach this hobby in different ways. For me, it is more about learning that it is about sleepless nights and OCD nightmares. The experts are not necessarily the last word on any part of this hobby, but the good ones may teach us something that we did not know before. We could then take that lesson and apply it the next time we buy a cartridge and want to mount and align it ourselves. For many of us, this hobby is a continuous learning experience. I appreciate anyone who is able to teach me something I did not know about set up, component matching, things to listen for, acoustics, music, just about everything in the hobby.
I disagree about turntable set up. I think it is all about precision. The most precise and easy to use protractors usually provide the best results. The more precise the alignment of the stylus in the groove and the coils in the magnets, the better the sound usually is. One can certainly learn how to set up an analog system himself, but if one is not that experienced, the help of someone who knows a bit more can usually make a pretty significant difference. If the guy is curious and wants to learn, he may then know more the next time around.
Just look at all the threads asking advice about DACs, tubes, amp matching, cable matching, record cleaning machines. The list is endless. People want to learn and occasionally, they are willing to pay for the advice.
To each his own, but I appreciate the advice of those who know more than I do. And sure, I'll tinker a bit more once they leave to see if I can improve things still further with what I have just learned. The interesting thing is that some audiophiles reach a level of experience where they actually know more than some of the experts who charge for their services.