How often do students switch off when the instructor shows a technique they have seen many times before? It’s because the student has a mental blue print of what is about to be shown and some of them have a tendency to switch off. The end result being no improvement or being worse off.
When the instructor takes the time to show anything students need to be extra alert. Is there something they have missed before, is the instructor going to say something different, is it going to be presented differently? You can only improve by picking up new detail and and then continuously practising. Improvement requires attention not assumption.
Both pictures of the Mona Lisa look exactly the same except for one small detail. When something is showed to me I enjoy seeing the same thing over and over again to see if I can spot the difference, this is what you makes you improve. You will only find this if you concentrate and look carefully. Remember this when the instructor is teaching.