Repetition is a really powerful tool, whether you want to master an art like Tai Chi or master your mind (or both) practice is vital. The daily practice of Tai Chi trains your body and if done with awareness also awakens the mind.
I have found that watching my 'wandering' mind has made me very aware , aware of the often subconscious thoughts the stuff that robs my energy and my concentration.
If thoughts persists in interrupting my practice I will take those thoughts to inquiry, usually Byron Katie's four questions. Knowing that I will do this later is often enough to quieten my mind. It has become a practice and the repetition has taught my body-mind that I will work on the issue later and so it allows me to return my focus to Tai Chi.
Practice what you want to become.