Typically, your microbiome only changes significantly when you have a major disease, take antibiotics (within the past 3 months), make dramatic dietary changes or with aging. In these cases, DayTwo may recommend re-testing.
In general, microbiome research is a relatively new field in biology. Current science knows how to profile your microbiome, but not how to alter it. We believe that in the future microbiome-targeted therapies will be available.