How long/how much is "good enough" - that is the big question.
Remember that your lungs and airways NEED mucus to keep them lubricated, so when you try to "get it all out" you stimulate them to produce even more mucus.

The goal is to do enough to get the mucus moving up and out, but not so much that you irritate your lungs and cause them to produce more mucus.

So whichever routine you use, according to my RT, should be about 10 cycles of active breathing/expulsion, or up to 20 minutes and stop. It's perfectly okay if you continue coughing up more stuff throughout the day. You can stop sooner if you can't sense any moveable mucus in your lungs-some days are like that.

Note to those with "dry bronchiectasis " my pulmonologist says you too should do airway clearance daily -you are forcing the damaged cilia to move so that anything in your lungs can't comfortably settle in.