To my understanding, the way healing works in the Cosmere reverts oneself to their perceived cognitive self. This is why Kaladin's brands don't heal, yet Lopen's arm grows back. With gold feruchemy, it would seem like one would still age. Their stored up health can only heal them so far, and their cognitive self would age. However, if one was able to have an absurd amount of healing, like a gold compounder such as Miles Hundredlives, AND they considered themselves immortal, would they age? I feel it is a reasonable inference to say Miles thinks himself immortal, considering his mentality seen in Mistborn, especially after he mentally moves beyond pain itself. If he imagined himself at a consistent age, believing that his healing prevented him from aging, and he always had copious, near infinite, amounts of healing readily available, I think he would achieve immortality. Plus, I feel like adding hemalurgy into the mix would only increase his already insane healing abilities, especially if he had a Trell spike that had some sort of power along the lines of healing. Thoughts?