if it ain't broke, don't fix it

Etymology
Attested since c. 1962, originally Southern United States English; popularized by T. Bert Lance in May 1977.

Proverb

 * 1) It is wise to leave something alone and to avoid attempting to correct, fix, or improve what is already sufficient (often with an implication that the attempted improvement is risky and might backfire).
 * I know it’s an ugly-looking antenna, but it gets the job done, and if it ain't broke, don't fix it.

Coordinate terms

 * don’t change horses in midstream
 * don’t change horses in midstream

Translations

 * Chinese:
 * Mandarin: 東西沒壞就別修它
 * Danish:
 * Finnish: älä korjaa sitä, mikä ei ole rikki
 * French:
 * German: ist es nicht hin, mach es nicht heil, repariere nichts, was nicht kaputt ist
 * Hebrew: מה שעובד ־ לא נוגעים, אם זה לא מקולקל, אל תתקן
 * Hindi: जो चीज़ खराब नहीं है उसे ठीक ना करें
 * Hungarian: ha nincs baja, ne javítsd meg
 * Japanese:
 * Polish: nie szukaj dziury w całym
 * Portuguese: em time que está ganhando, não se mexe
 * Russian: не сломалось — не чини
 * Spanish: si funciona, no lo toques
 * Swedish: om det inte är trasigt, fixa det inte
 * Ukrainian: не зла́мано - не ладна́й