The Biggest Subject Avoided by most teachers and students of Classical Guitar is Right Hand alone practice. It is seen as an advanced technique that only the pros go through.
An Even Bigger Subject Avoided by nearly every teacher and student of guitar is Left Hand alone practice. It is generally assumed that only someone like a Segovia has the disicpline to pursue something so enigmatic.
Well Guess What ? Until you practice both hands alone before practicing both hands together, you'll flounder around on the guitar for years and I'm talking about all guitarists, beginner to advanced.
Both hands practicing in concert on the guitar after practicing them alone, and sometimes away from the guitar is not a choice....it's a requirement. Not doing so is simply Not An Option !
ALL interpretive techniques employed when playing music rely on on a sound structure and refined details but unfortunately most want to start at the top and tackle the music first.