Another bad habit I've noticed recently, exhibited even by published authors, is word inconsinstency.
My favorite was in a manuscript where the author actually made up an invention, and its corresponding abbreviation and/or nickname. Example: Saab Version I would abbreviate to SVI. The nomenclature then appeared a number of different times after introduction as both SVI and SV I.
When it's your own invention, how embarrassing is that?
Would you go out in public with one black and one white sock on? Don't leave discoveries like these to your editor, or even worse - to an agent or publisher.