Here is my view.
NAD+ replenishment will likely slow down many aspects of human aging or even reverse it modestly. For certain disease conditions it may even work wonders. This is what all the research is telling us so far. As we grow old NAD+ goes down and causes all sorts of problems. However, when damage is already done, additional NAD+ won't allow the body to fix all of the damage that has accumulated. Our genetic programming as adults doesn't allow for full regeneration of tissues. Even if you boost NAD+ to the max, without the genes of embryogensis active, only a portion of the damage will be reversed. For example, a very high level of NAD+ won't trigger the body to regrow lost limbs or replace damaged skin. For that, we'll need to activate a range of genes that are not turned on by NAD+ replenishment. Also, I'm not sure if the body has any means to remove certain waste molecules such as glucosepane. To reverse aging all together, we'll need a range of therapies. But I think of what's available right now NR is probably the top supplement someone can take for overall aging.
Fair. Even thought NR can fix many problems, the value is in prevention. NR is the best and only solution for anti aging and even age reversal to a certain degree. Any wise person should take NR after 30. I will get my kids on NR at 25.