May be its a ridiculous or trivial question but many things in life are following the Gauss curve or a hump dromedary curve in term of efficiency. Many of us reported a long burn in period for the DS (or for many other devices more generally) but what happen when we reach what we think or feel to be the top?
How much time the nirvana?
Is there not several camel humps or a very slow deterioration of the sound quality? How much time for that?
May be when we reach the moment where an irresistible desire to change the material is here (all audiophiles knows these sensation) it is because the “burn out” work gone in this sense…