Do our bodies get used to or immune to the chains of probiotics its receiving after some time? if so , it is necessary to change brands or types of strains after certain periods?

We believe probiotics is unique and foundational -- in order words, that the strains are more essential than others. Thus, you can rotate others (including fermented foods in your diet), but this is the most complete SBO (soil-based organism) formula and there's no need to change.