@suzieq11 There are two types of nebulizer cups, disposable - meant for a single use by one person, and reusable - meant to be used for three to six months.

The disposable ones (generally) will not withstand boiling or other sterilizing techniques. But biofilm can attach over time, harboring mycobacteria, so frequent replacement is necessary. In my opinion, after a lot of reading, that would be every week or two if you are at risk of infection, and every week if you have MAC. When my Mom, who had bronchiectasis, asthma and congestive heart failure, was hospitalized for many weeks, the disposable nebs were replaced every 3 days by the respiratory therapist.

Reusable cups are made to withstand sterilization by boiling, microwave steamer or a baby bottle sterilizer. But your concern about the plastic degrading is real, that is why frequent replacement is recommended. The interval varies by manufacturer from 3-6 months. When I used mine daily, I replaced every 3 months (I now use a different type, which is replaced when the flow weakens.)

Did you get any guidance from your pulmonologist about how often to replace the nebulizer cups?