How long does a delinquent payment REALLY stay on your credit report?

I've always assume 7 years. 7 this, 7 that. 7 seems to be the default number.

I made a post last month about paying off my 120+ late delinquent debt and a redditor mentioned 4 years for delinquent debt. He seemed very confident in his answer.

But digging through the internet, I still keep seeing 7. Where does it say 4 years?