Truss rod adjustments should only happen if the "relief", typically .010", is out of order.
Hold down the low E at the 1st and 12th fret, look under the string, do you see a slight gap?
Conversely you can tap the string with your right hand thumb at the 8th fret, you can hear the clearance, like a wee hammer on/pull off.
Too much gap and the TR is too slack or the strings are too big.
Too little gap and the TR is too tight or the strings are too small.
Adjust as needed. The old time Guild owner's manual says to do this "at full string tension."
I ALWAYS begin a TR adjustment by backing it off, because the nut is often frozen in place, not a good way to start tightening something, but a good way to snap it off. Crack it loose in CCW direction, I unthread the nut most of the way, blow out the dust, and put a drop of fine machine thread oil on the thread. Bring the nut back down, seat it, and then tighten as needed.
Get a nice 24" heavy rule, the handy one for checking neck angle, lay it over the frets, you can see a lot this way.
On my JS2 bass, the neck has a very noticeable dip with no strings on at all, the neck is permanently bowed and even cranking the TR all the way - 1/2 turn from just seated - doesn't change a thing.
My 1972 Martin D28 didn't have a truss rod and I never gave it a 2nd thought.
Leo didn't feel that he needed one in the Broadcaster/Telecaster, but people like to tinker, so he put it in, under pressure from Forest White and others.