Today I did my first nest change out on two cavities.  As the next two weeks go by I will be conducting Nest changes on the cavities with young.  A nest check is done every 5 - 7 days. A nest change, where the bedding is replaced, is done when young are about ten days old.  This eliminates nest parasites, especially Blowfly, and helps keep the nest sanitary.  While a nest change is not mandatory of a purple Martin landlord, it does allow one to help their martins raise a successful brood. 

Below is a check of my T-10 house and a change of a chirpyNest cavity