I have been using the smartvest for about a year. Everyone has a different experience cuz our BE and/,or MAC is different in severity, location in the lungs etc. what worked best for me after experimenting was nebulizing 7% saline at the same time, stopping the vest and doing huff coughing whenever i feel the need to cough -- which can vary a lot. I get up the most mucus this way. My doctors approved.