Once The Simpsons reached 12 seasons, fans started referring to the show’s Golden Age, and they were right. There is a long run of The Simpsons that features their strongest combination of talent, including the likes of Conan O’Brien and Brad Bird, and the epitome of irreverent, absurd satire that is The Simpsons’ trademark. There is more to The Simpsons than the Golden Age though. The further along The Simpsons made it, the more nuanced their humor became.

It’s the subtle evolutions of the show that have kept it relevant and vital. By nature, once you’ve done 12 seasons (over 200 episodes) of something, the process itself begins to reflect its longevity, and the very time the show exists in requires a different approach.

There have been five distinct eras of The Simpsons so far, four of which are as funny and satirical as the Golden Age. Now that they’re all playing out of order on FXX’s “Every Simpsons Ever,” you might not even notice the difference. But, if episodes from these eras come on, it may help you appreciate them if you know where they fell and how The Simpsons was adapting to the world at the time.

Early Years (Tracey Ullman Shorts Through Season 2 or 3)

When The Simpsons began it was a rather straightforward comedy about a dysfunctional family. The big controversy was that Bart said “hell” and “damn,” which seems quaint now, and a crutch the show soon abandoned. Even the early seasons exhibit fast evolution from straightforward plots to more nuanced themes and social commentary with episodes like “Lisa’s Substitute.” When they got next level deep and funny in season three, which included “Stark Raving Dad” with Michael Jackson’s uncredited cameo, and “Flaming Moe’s,” in which Homer started to take on greater status as the bumbling everyman hero.

Golden Age (Seasons 3/4 Through 9)

Whether we include season three or wait until season four, there’s no denying the following years are what made The Simpsons the cultural touchstones they remain. The Simpsons tackled big picture issues like groupthink, religion, and gun control, making Springfield a microcosm of the world at large. The most iconic episodes surely come from this era, but that doesn’t mean any that came after are bad. They all benefit from the world established in the Golden Age when minor characters became the stars of their own episodes, and the family gained more depth. Bart was no longer just a troublemaker and Lisa was no longer just the smart one. Homer became the stand-in for the everyman and could be as naive or as indignant as we all can be.

New Renaissance (Seasons 9 - 13)

As the writing staff shifted, and The Simpsons had simply done every imaginable story including sending Homer into space, many fairweather fans gave up. If there were to be a bad episode of The Simpsons, they might be likely to fall in this rough patch when the show was figuring out what to do next. But if you wrote The Simpsons off, you missed some great experimental episodes like “E-I-E-I-(Annoyed Grunt)” where Homer inadvertently invented genetically modified crops, or “Sweets and Sour Marge” which spoofed Prohibition and action movies, or episodes testing Homer’s relationship to other characters like “Homer Vs. Dignity” and “Homer the Moe.”

Postmodern Period (Seasons 14 - 17)

Once you’ve been on the air for over a decade, you become part of the history and society which you are documenting. Now that The Simpsons was part of pop culture, they had to become a bit self-referential. You could catch Lisa reading from “The Simpsons: The Complete Guide to Everything” or find Homer holding up a map and asking the audience if they read all the jokes, saving us all the trouble of pausing the show. There is a bit of overlap. Even some late Golden Age era episodes make references to past episodes like Bart’s elephant Stampy and Lisa’s frustration with the resolution of “Who Shot Mr. Burns?” These seasons are where The Simpsons really owned it.

Post-Simpsons Movie (Seasons 18 - Present)

The Simpsons creator Matt Groening and producers James L. Brooks and Al Jean said that making The Simpsons Movie, released in 2007, reinvigorated their passion for the show and you can tell. The episodes they were working on concurrently with the movie began airing around the following year in 2008 and you could feel a certain bite return. The Simpsons would take shots at popular and classic movies from The Da Vinci Code and superhero movies to All About Eve, and hot-button topics like immigration and teen YA novels. They finally went HD after 20 years and even hooked up Ned Flanders and Edna Krabbappel. There are still elements of postmodern and renaissance periods, but really it’s a new Golden Age for The Simpsons reinventing themselves in the new TV landscape.