How do you usually tell when you're watching a zombie-era episode of a TV show without knowing what season it's from? For cartoons, I feel like HD or cleaner animation often correlates with a dip in quality. That doesn't mean the show stopped being good altogether, it just means it's no longer in the golden age. See post-Season 9 Simpsons or post-movie Spongebob for good examples of this. There were still some individually good episodes but the overall quality of the shows weakened.
What are giveaways you've noticed that you're past the golden age in live-action shows?
What are giveaways you've noticed that you're past the golden age in live-action shows?