Setting up neck dip (truss rod) and action should be done in "playing" position too, due to that gravity thing. Handy to get close on the bench, but fine-tune in your hands.

Oh, yeah, it rains. It does not. It is hot, then it is winter. You may find your action all screwed up all the time. Action is fine, check truss rod.

There is a set sequence to do this setup thing, to avoid going to-and-fro all the time, getting nowhere. Someone please list this and pin it on the main notice board for all to see. Hmm, separate discussion of nut height?

So now our guitar plays like a dream.. the strings feel just right, it sounds awesome unplugged, but now we need to plug our beauty in and make sure that we get that red-lace pantie dropping sound.

this is probably the most subjective part of your setup, and what sounds right to you might not be your buddies perfect setup.

for the humbucker guys
https://www.premierguitar.com/articles/22114-mod-garage-humbucker-height-adjustment

and adjusting pole pieces
https://www.seymourduncan.com/blog/the-tone-garage/fine-tuning-the-adjustment-of-passive-humbuckers

and for the hockey playing ladies
https://www.premierguitar.com/articles/How_to_Balance_Pickups_on_Strats_and_Teles

some further considerations

adjusting nut string height

cleaning and conditioning your fret board

I hope this helps, what I can say is there is a ton of information out there, on all of the above topic, please do further reading/watching if even just to better guide the person who will be doing your guitar setup,
but sometimes even when you send it in for a complete setup..you end up having to do it yourself..
My own guitar I ended up butchering the nut to file it down enough to actually be able to play it, after sending it in, and specifying that as one of the problems.. thus starting my slow arduous delve into the world of guitar setup.

Disclaimer.. I Am by no means a expert on the above mentioned topics, and this guide is as much for me as it is for you.

The nut slot thing - After doing it from the string side a couple of times (without the correct nut files...) and getting it wrong here and there, I now take out the nut, and sand away material from the bottom. Too low? Add a shim. No nut files required, unless you make up a new nut. This of course assumes that your guitar's nut has the slots cut to the correct radius to start with.

And the fret level thing - I have found on several guitars (should not happen on real good expensive guitars?) that removing the strings, cleaning the fretboard, doing some fretwork, and re-stringing, re-setup and so on, will make some frets move in their slots, giving you high/low spots where you did not have before. So, all this is an iterative process, small improvements until you finally get there. I live in hope.

modulator

modulator The nut slot thing - After doing it from the string side a couple of times (without the correct nut files...) and getting it wrong here and there, I now take out the nut, and sand away material from the bottom. Too low? Add a shim. No nut files required, unless you make up a new nut. This of course assumes that your guitar's nut has the slots cut to the correct radius to start with.

This been my first attempt at guitar setup.. it came out fairly well, gone from unplayable, to brilliant.. something you expect to be sorted out at the paid for setup at the music shop.. but alas..
and yeah behindhand experience .. I did realize afterwards it would of been better to sand the bottom.. my next trick is to try make a Bone Nut.. and WAS in the process of cleaning the bone.. but that too has seemed to gone south... I think the Gardener has chucked the bone.

We are extending the thread here, but working form the string side is OK if you have a false fret to put against the nut, at the height you require the slots to be. Easy on a nylon string (if flat fretboard...) but a hassle on any radiused neck. And, one would want the guitar to leave the factory with the correct setup, anyway.

Bone nut is a must-do, fresh bone work better than sun-dried/bleached pickups. Only hassle is the rather sticky dust. For nut files, modify several mini-hacksaw blades, grind off normal hacksaw blades, and save old wound strings to help saw/polish. Some small needle files help to, you can grind flats on the round ones to make a "nut" file giving a sort of rounded bottom slot. Sort of. Hmm, and buy a "jewelers saw", those blades are very thin, just right for light gauge trebles. For perfectionism mill out guide slots at exactly the correct spacing. For DIY, vernier caliper, pencil, saw.

Tuckstir and for the hockey playing ladies

Bwahahahaha. I laughed so hard at this!! Brilliant.

I have found a really great setup vid on bass guitars. It runs to around 1 hour, 20 mins. Am posting it under the bass section. The guy shows the setup on a cheapie Ibbie Soundgear Gio which is fantastic for me, because that's exactly the cheapie bass I own.

Anyone interested, look for the vid there!
dh|

Tuckstir this is the same vid from the other thread? looks purdy dang awesome - gonna try some of these out this w/e.

thanks a bajillion times mate
dh|

I'll post this series as the get released.. seems good and clear .

Next ones release

couple of new ones

Does any of this matter? Yes. I have posted on making a special tapered neck shim for my first guitar, to lower the action. Helped a lot. That guitar has always had a "loose" truss rod. It seems I am forever re-tightening it. Played it again recently, put it aside. Tried again, put it aside. Decided to lower the saddles and decrease the dip. Yup, the truss rod was "loose" again. After the quick (re-)setup, the guitar played better, yes, but the improved instrument dynamics (the vibes in your hands) and tone surprised me. Just a tighter, more "solid" neck made a huge difference.
I also see (imagine?) that the "set" the neck acquired through many years of string tension without truss rod counter-tension has decreased? Wood is a living thing, look after it.