Forewarned is forearmed.

Advance warning gives a person time to prepare, reducing surprise and improving their ability to meet a threat, difficulty, or decision. Information received early can therefore function like a practical form of protection.

The saying encourages attention to cautions and signs of possible trouble. It does not promise that preparation will prevent the problem, but stresses that readiness usually leaves someone in a stronger position than ignorance does.

Use it when a warning, forecast, or prior knowledge enables sensible preparation for a possible problem. It can introduce practical advice or justify precautions, and may be used after sharing information that someone should take into account.