I was cleaning out the fridge yesterday, ran across a couple of tacos in a ziploc bag I forgot I stuck in there from last week. My ass was sitting there like "aiight... what day did I make tacos? Shit, that was Monday... It MIGHT be cool... Nah, I ain't taking that chance"
Also found some pizza in there from the Saturday before that and I just knew better.
My usual rule is 3-4 days depending on what it is. Sometimes the shit was so good I really contemplate eating it on day 5 or 6.