Guidance on schematics:

Clear - Understandable by a knowledgeable person
Concise - No extra "fluff", but notes added as necessary
Compete - Everything necessary to replicate the work is present
          Sufficient detail to make clear what is going on
           - part or module identifiers
           - pin numbers 
           - net names
Correct - No mistakes
Neat    - Orderly, structured, legible

A correct schematic may look very different depending upon context.
There are no simple rules. Judgment is required.