Could it be useful to gauge the color of sputum as it relates to timing? In other words, the first two huffs out are a deeper color than the last several huffs out. Somewhere along the line I picked up that the darker mucous has been down in the lungs longer. If you start out greenish, but end with pale yellow, to clear, then that might indicate less likelihood of infection. If you start out greenish and end greenish, then possibly something could be brewing. This is the way I’ve thought about it I don’t know if it’s correct? For me, how much I clear, how I am feeling, how much I get done during the day, frequency of exercise, etc. are bell weathers of health.