You bring up an important note - whether one is adjusting only their guitars and one who is adjusting guitars for others. It is likely more important to MEASURE AND RECORD settings when adjusting for others. If the instrument comes back in two weeks, it would be good to know what clearances it had when it left, and what it has now. In my recliner, it isn't as important. Also, using tools, numbers, and documentation makes the client feel like you know what you are doing - then you can up your fees!I worked on my own guitars and as a guitar tech without ever using any measuring devices until I was well into my 50s.
Then one day as I squinted down the neck to set relief I concluded that my eyes had stopped working as feeler gauges, so I moved to straight edge and either feeler gauge or whatever was near the top of the tools pile on the bench.
I don't need to know the number of thousandths my relief is set to, but if chasing an odd neck problem or removing and storing a neck to do other work on it or the guitar, I might want the number for reference.
Same with a neck I'm going to do a heat reset to, I want to know how bad it was and confirm I heated and over bent it enough, since that's kind of instinct and doesn't always come out as expected.
I have to admit all the tech chat here also played into my bringing feeler gauges in from my garage mechanics tools to use on guitars.
I set up tons of guitars for other players based on watching them play and setting relief and action to match their technique, but only in the last 5-7 years learned the numbers associated with my relief settingsYou bring up an important note