Well it stands to reason if they're good for bad knees that they would help keep your good knees good?
Forgive me, for I am derp today.
As far as the NRc's, I was looking at them because they're the cheapest out of the 3. But they seem to be in between freestyle and all-mountain which is about what I was looking for. The Bosses seem more worth it, as do the Flows. Honestly either would be a huge upgrade for me, and hopefully either would be something that would keep their condition from the day I got them to 3yrs later. One can only hope!