I’m gonna go there once again. There are those, like myself, who not only measure things like neck relief and string heights and pickup heights, we suggest that others do likewise. There are others who say they don’t need to measure because they just adjust things by “feel” or amount of fret buzz. That’s fine. I think you’re probably not doing as good of a job on your adjustments as you could be, but I’m not the boss of you. I get it.
The people I really do not understand are the ones who are actively hostile against measuring things.
They do indeed exist. Not only will they tell you that they themselves do not measure things, they will tell you that measuring things is an inferior way to go about guitar setups. I have been told that measuring is “useless” and will steer new players wrong. Like seriously angry about it, too.
I honestly don’t get it. My typical response to them is that more information is always better than less information. I might also add that my hat’s off to them if they can reliably tell the difference between 10 thousandths of an inch and 12 thou without measuring. Because I cannot. (And neither can they.)
To be fair, their point, as far as I can understand it, is that setting your neck relief or string height or whatever to an “arbitrary” number is not the best way to get the instrument playing the way you want it to. Because you’re a special snowflake and no one can tell you what The Matrix is you have to see it for yourself. Or something.
If the manufacturer of your instrument recommends a neck relief of 12 thousandths of an inch, that’s not “arbitrary.” It’s a number that reflects how they made the instrument and designed it to work. That’s not to say you can’t change it. Of course you can. But it’s not a bad starting point, especially if your instrument is out of whack or experiencing a problem.
Like I say elsewhere on this site, the numbers I recommend are my default ones. They are, in my experience, ones that will result in an instrument playing without problems. And, on the flip side, if you use those numbers and a problem remains, you can reasonably assume that you have a deeper issue and you should take it to a pro.
The numbers I use and recommend are sensible starting points for most instruments. Use them if you’re unsure. Or if you’re trying to diagnose a problem. Use them as a starting point. And then as you get to know your instrument and develop your own playing style, tweak them to your liking. I do. And I say so very clearly on this site.
Suggested numbers do not hurt anyone. But telling people not to use any numbers does.