Unless you are aware of some papers I haven't read (which could be the case, and I would love to get the references if so), you are making a huge assumption here that D-aspartate is increasing testosterone production through interaction with NMDARs. In a high protein diet, you are going to get much more than 3 grams (the typical recommded D-Asp dose) of the "endogenous agonist" of NMDARs, L-glutamate. So, why doesn't L-glutamate stimulate testosterone synthesis, or at the very least keep production through this putative mechanism saturated in a high protein diet? The research would suggest that D-Asp interacts with NMDARs sure, but clearly there is more to the story.And to answer the OP, a lot of the cycling recommendations you will find are basically arbitrary. For something that has been popular for a couple years now, near as I can tell it's still all pretty much guesswork. If you "feel" something from taking it and you still "feel" it after two or three months, I personally don't see any necessity to stop. If you want to be better safe than sorry, as there is the general idea that taking something for too long will throw your body out of homeostasis (which I think is often overblown for supplements), then follow the general recommendation of about eight or twelve weeks on, followed by a break of at least four weeks.
