What is the longest establishment of a Chekov's gun?

After reading about Chekov’s Gun (warning: TV Tropes) in which a seemingly inconsequential detail is mentioned early in a piece of work only to become essential to the plot later, I was wondering what were some especially, notably long delays between the setup and payoff?

I remember in Arrested Development, they were making sly jokes about Buster losing his hand from very early on in the first season but the actual act didn’t happen until quite far into the second, making it a year’s delay.

But my absolute favorite has to be Agrajag from The Hitchhiker’s Guide to the Galaxy which was finally revealed in the 3rd book, making it a 3 year delay.

I’m sure there are examples longer than that. What are some of your favorites?

The black & white stones in Lost, shown in an early episode, and not explained until the end of the final season.

Kilgour asks if he can tell the spotted snake joke in Sten, but doesn’t until 6 books later, in The End of Empire.

The crannogman, Howland Reed, who was first mentioned in A Game of Thrones but we’ve still never actually met. I’m pretty sure that he’s going to be essential to the plot of the series in the future. He was present at pretty much every major flashback.

The climax of the web comic, 8 Bit Theater. He set up the (shaggy dog) joke something like 8 years before the end of the strip.

Yeah, that’s got to take the cake, timewise. I’m also still waiting for an “Arkensaw” joke in Erfworld.

Did Douglas Adams know he would do that when he created the bowl of petunias in the first Hitchhiker book? Or was that a ‘retrofitted’ Chekov’s gun?

Got a link to the setup?

Episode 7 from March 2001, paying off in Episode 1221 in February 2010 (linked above). Nine years, and based on a throwaway line.

Even without the set-up strip, that’s a thing of beauty.

I don’t get it. Where’s the joke?

nvm, misremembered plotpoint.

I recognize the individual words, but not the meaning or humor they were meant to impart. Man, I feel like an outsider reading those 2 strips.

Technically speaking, that’s not “Chekov’s Gun”. Chekov’s Gun is a CONSEQUENTIAL detail that DOESN’T get used later. If an audience sees a rifle hanging on the wall in act one, they’ll start speculating on when it will go off. If it never does, they’ll leave the theater disappointed. Chekov is saying that you shouldn’t introduce intriguing elements into your plot that never pay off.

Would Nibler’s shadow in the pilot of Futurama count? I never noticed it until it was pointed out in Season 4.

That’s an Easter Egg in my view. I don’t believe anyone who’d say they spotted that shadow in pilot.

I just rewatched the pilot on Netflix the other day and I don’t remember seeing Nibbler’s shadow. I wasn’t looking hard for it, but it was in my mind to keep an eye out.

That may be my fault though, because sometimes I’m distracted by hey look a bird!

Harry Potter’s scar is mentioned throughout the books but it’s not until the 6th you could have any idea it’s a horcrux and vital to killing Voldemort. (In the 7th it’s actually revealed to be one but most had clocked that one after learning about horcruxes.)

In that case, Lost is the biggest Chekov’s Gun in history.

Chekov’s Howitzer