Every 100 years but not every 400 years! Isn’t it fun?

Small correction, it’s every fourth year except every hundreth year except every 400th year. I’m assuming the misconception comes from the last time it was a 100th also being a 1000th (2000) but the next time a leap year will end in 00 is 2400

I’ve certainly never met a perscriptivist who I held in higher regard than Mark Twain.