Some people choose to rotate their probiotics every so often in order to introduce their gut to new bacteria. Our philosophy is that if their gut is impaired, however, people need to stay away from some strains so rotating may not always be a good idea.
We feel that someone might be ready to "graduate" and add new strains only AFTER their gut is healed enough. We've had people that have rotated in another product too early in their healing and ended up with bad reactions.
That is why we are launching Primal Gut powder soon. For the people that have achieved healing with GutPro and want to add new strains, but want to stick to our approach of how we balance the strains (not too much d-lactic acid, balanced approach to histamines, etc)
On a last note, GutPro can be taken indefinitely. Some other product have a large amount of a single strain, and you would definitely want to rotate those products (or simply avoid those products).