Yogi: How do I know that the quality of my mind has improved?
Sayadaw: Good quality of mind or bad quality of mind, you can know through how the mind feels. If you think in a positive way, you feel positive; if you think in a negative way, you feel negative.
When defilements arise, they are accompanied by suffering feeling – e.g. tension and burning sensation. You can then say that it is bad quality of mind.
Now that your awareness is getting better and better, how do you feel?
The mind has more freedom – it is lighter, and has interest. These are wholesome qualities that you can feel and know.
Wholesome or unwholesome qualities are accompanied by pleasant and unpleasant feelings. When there are wholesome qualities, the mind is relaxed and free; that you can feel.
You need to check your mental state again and again; and slowly, you can know if the mind quality is good or bad through how you feel.