I get a CT scan one year, x-ray the next - a scan would be ordered if anything new showed in the x-ray, but so far I am stable since October 2019. At that point my ground glass opacities cleared and nodules had shrunk, but my sputum culture was still positive (I don't remember the numbers.)
I do not have MAC symptoms, but I have had exacerbations - respiratory illnesses where I had to increase my airway clearance, add duoneb (a 2 medication Rx) for a few weeks. A couple times I had to take oral steroids to get my asthma under control, or an antibiotic short term for bronchitis - and I had whatever went away. This did not happen when I had MAC - antibiotics would make me feel better for a week or two, then I would feel as sick as before, or even worse.
I also cough every day, more or less depending on how good my airway clearance, asthma, allergies, and exercise. Running with the dogs or kids, dancing fast or riding my bike, guarantees a coughing fit. That is no fun since Covid started - people always look at me like I have "the plague" even when I tell them it's just my bad lungs.
If I get even a hint of illness - more mucus, colored mucus, heavy chest, or just feeling unwell, I double my airway clearance and saline, drink more water and herbal tea to thin the mucus and get extra rest.
Sue