Measure twice before you cut once.

Check dimensions, facts, or plans before taking an action that cannot easily be undone. A little preparation can prevent costly mistakes, wasted materials, and repairs later.

Though framed as workshop advice, the saying applies broadly to consequential decisions and tasks. It recommends deliberate verification before commitment when errors would be difficult to correct, rather than exhaustive review of every ordinary action.

Use it to urge someone to confirm details before a consequential step, such as making a purchase, sending an important message, altering a document, or beginning practical work. It can be practical advice or a gentle reminder to slow down and check.