I think any reader has at least once wrapped his head around the fact that time basically never passes in the MU.
While it is somehow acceptable, considering the characters are so iconic that changing/aging them would be fatal to their general popularity, its still a pretty big atmosphere-killer sometimes, so I often come up with explanations for my own head-canon to make it a little explainable.
The easiest, at the latest after Age of Ultron, is: Time is broken. Because of the many time travels, reality warpings etc the timestream is irreversible kaputt and thus time passes in such a strange way.
But the explanation I like more is a quite common theory which includes Franklin Richards, who is especially notorious for never aging at all:
He is a powerful Reality Warper, but also a scared littled child who is afraid to grow up and afraid of his friends and loved ones to die at some point.
So he subconsciously manipulates the strings of reality to fit his idea of the perfect status quo.
Do you also sometimes think about this?
Have your own theories/explanations?