Just now, this happened:
Me: Is my math right? Is our next anniversary our eighth?
She: That’s right.
Me: Huh. And how long was the contract for? 10 years?
She: Hey!
Me: Heh.
She: Anyway, it wasn’t a contract, it was a warranty.
Me: Hey!
She: Heh.
-FrL-
I hope we still amuse each other at 90.
Heh, you guys sound like me and Mr. S, and our ten-year warranty expired almost 7 years ago. We still crack each other up out of the blue.
I think the couple that snarks together stays together. 
My husband complains that he has too much “mileage” on him (referring to the movie quote from Harrison Ford as Indiana Jones, “It’s not the years, honey, it’s the mileage.”), and tells me to trade him in. I tell him no, “sucks to be you,” and we tease each other for a while in that fashion.
My husband says he doesn’t need to say he loves me; he figures that “I love you until further notice” took care of all that. Ain’t a comfortable relationship grand?