Know when to fold ’emKnow when to fold 'em is a popular saying based on a Kenny Rogers song and poker slang. 'You have to know when to hold 'em and know when to fold 'em'. It means knowing the difference between when you have a good hand to play and folding your hand when you don't. More is a popular saying based on a Kenny Rogers song and poker slang. ‘You have to know when to hold ’em and know when to fold ’em’. It means knowing the difference between when you have a good hand to play and folding your hand when you don’t.