New or old strings? Neck or bridge pick up? Good quality noiceless cable?
Humbucker or single coil? Does pickups pick up some electromagnetics
from other things in the room, like computer screens, light tubes, dimmers,
air conditioner, WIFI and so on ? Anything of this can add a conflicting sound
to the clean sound from a string and "confuse" the tuner
I mostly use my ears when tuning my guitars ( every guitar behaves different )
Very good point. I play with my computer in front of me, phone on me etc. Thanks!