I was fortunate enough to be mentored by Master Knight tonight before class.  While we were working on Green abd High- Green self-defense and poomsaes, he stressed proper stances and hand placement.  These are things you don't normally focus on because you're trying to remember the movements.  But I understand why what he was saying is important.  You can never do the basics enough.  Being proficient in the basics isn't just important for white belts; it's the foundation of success for every belt level.  Mastery of the basics determines how good a student will (or won't) be in the future.  This includes poomsae quality, sparring effectiveness, self-defense techniques, and even your ability to teach others.  So never stop doing them.