When retiring his comic strip Bloom County, Berke Breathed remarked “a good comic strip is as eternal as a ripe melon.” Personally, I think that’s bullshit, and reflects more on Breathed’s motivation, or lack thereof. A good comic strip lasts a lifetime. We still pass around clippings of The Far Side and Fabulous Furry Freak Brothers, decades after they were printed. A cartoonist who can’t perpetuate over changing times has inked themselves into a corner. Or dried the well.
If a comic strip is still hilarious long past its sell-by date, it is a successful comic strip. That is the acid test.