How long before anyone has seen improvement in their MAC journey?

A few months.

@sharondig not sure what you mean by "little change" but under the 2020 treating guidelines, if your sputum hasn't converted by 6 months, you need to change up your treatment regimen. For many that may mean adding Arikayce, switching to daily Big 3 if on Big 3 only 3x a week. It is going to depend on your individual circumstances, but the thinking is that if you have not sputum converted by month 6 on your current regimen you are not likely to. As for CT changes, not everyone sees improvement on CT, it may depend on your presentation, and cavity disease is its own separate discussion. Have you discussed with your doctor the lack of change? Do they have a plan for addressing? Are you seeing an NTM specialist? I think an NTM specialist is instrumental, particularly where initial treatment is not getting results.

@bayarea58 Do you know if your doctor ordered sensitivities with the AFB culture? At one point I had been on the 3 drug regimen (this was back in 2014, maybe) with Zithromax as one of the drugs. I was on it over a year, taking 500 mg x 2 da/week and 250 mg x 3 da/week. When she finally decided to do another culture with sensitivities it came back as Azithromycin resistant. I was livid. I know things have progressed in the treatment of NTM illnesses, but this ended almost catastrophically for me. Thankfully, I was eventually referred to another doctor who was able to get me back on track and on the road to healing.

I'm not sure why but my cough disappeared after less than 2 weeks on azithromycin, rifamputin, and ethambutol and I have almost no throat-clearing after 5 weeks (it was constant for a few years).
I will likely still be on meds for a year or two--I don't want that cough to come back if I can help it. The doc did say he may let me drop the ethambutol in a couple months... the fatigue is a real problem for me.