I'm a fan of the Comics Code model (give or take a few years), myself, especially since a lot of companies (especially when dealing with superheroes) seemed to try to expand or rebuild their titles at around the same times.
I mean, you figure in the years leading up to 1970, Charlton and Tower had their heydays, DC tried to reorganize/reboot almost all its heroes, Marvel starts sort of a villain focus and Spider-Man and the X-Men have overhauls, there's an explosion of horror comics, and so on and so forth, plus the Comics Code gets revised. With all that going on, it's a pretty darn good signpost.