When you reread Marvel Essentials stories from the 60s and compare them to DC Showcase from the same era, you really appreciate the genius of Stan Lee and his cronies. The idea of anchoring characters to a known time and place was a real departure from DC’s approach, where characters lived in the fictional Metropolis or Gotham. However, Marvel’s great idea eventually headed south, somewhat. Spiderman, who started off as a teenager in 1962, watched the Twin Towers crumble when he was only in his twenties. 

We want time to be a strong dimension of our narrative framework. This implies that our characters age, and consequently, that they evolve because they are aware of their own mortality or because they feel time pushing them in the back, which forces them to accelerate their actions.