Don't leave home without it.

“Don’t leave home without it” is best known not as a traditional proverb but as a late-20th-century advertising catchphrase, popularized in the United States through American Express campaigns urging consumers to carry an AmEx card while traveling. The line became part of everyday speech as a shorthand reminder to bring an essential item—especially something that provides security or access (money, identification, phone, etc.). Because it circulated widely in mass media and was repeated in many later ads and parodies, it is often encountered without attribution and is sometimes treated as “anonymous,” even though its cultural prominence is tied to that commercial origin.

Taken literally, the quote is a practical admonition: before stepping out, make sure you have the one thing you’ll regret forgetting. Idiomatically, it has broadened into a general principle about preparedness and risk management—anticipating needs and carrying what enables mobility, safety, or problem-solving. The phrase’s punch comes from its absolute framing (“don’t”) and the unspecified “it,” which invites substitution: the “it” can be a credit card, a passport, a tool, a habit, or even a moral or spiritual resource. Its lasting resonance shows how advertising language can migrate into common usage and function like folk wisdom.

1) “Don’t leave home without them.”
2) “Don’t leave home without your [card/ID/etc.].”
3) “Never leave home without it.”