Is there an idiom/word/proverb that says not to change a perfectly good thing or something that works?

  • Hello, and welcome to the ELL. Your question could be much improved by providing some more context. See tour.
    – fev
    Commented Aug 4, 2021 at 7:17
  • 'Do not look a gifthorse in the mouth' is tangential but related.
    – P i
    Commented Aug 5, 2021 at 12:31
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    Related: Sufficient unto the day is the evil thereof. (In more modern language, “Do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.” But the “Sufficient unto the day” formulation is proverbial.)
    – MJD
    Commented Aug 5, 2021 at 13:33
  • @MJD Matthew 6:34
    – Click Ok
    Commented Aug 5, 2021 at 19:56

11 Answers 11


If it ain't broke, don't fix it. (informal)

If it isn't broken, don't try to fix it.

Edit: You could leave out "try to" (I've heard it both ways), but the point of the proverb is that if you try to fix something that isn't broken, you won't be successful.

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    Definitely heard "don't fix it" a LOT more than "don't try to fix it". Expression definitely sounds American in origin but it's permeated quite well; I would definitely expect it to be understood if I said it here in Britain.
    – Muzer
    Commented Aug 4, 2021 at 14:30
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    To be clear, the idiom is the sentence "If it ain't broke, don't fix it." I've never heard anyone say "if it isn't broken, don't try to fix it," and it would probably sound kind of funny if someone actually said that. Commented Aug 4, 2021 at 16:12
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    "If it ain't broke, fix it until it is."
    – Mark
    Commented Aug 4, 2021 at 22:07
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    I'm not sure that the point of the proverb is that you won't be successful; rather it's that there's a risk that in trying to fix it you will break it, and since it's working fine as-is, there's little point in taking that risk. Commented Aug 4, 2021 at 22:34
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    The wording “ain’t broke” is intentional. It’s meant to sound like advice handed down from an uneducated Southern American farmer. In other words, stop overthinking it and use common sense. phrases.org.uk/meanings/if-it-aint-broke-dont-fix-it.html The phase “ain’t broke” ain’t broke; don’t fix it. Commented Aug 5, 2021 at 12:10

"Leave well enough alone."

Related, "Let sleeping dogs lie."

I've always heard user3169's answer as "If it ain't broke, don't fix it."

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    Both of your suggestions are close, but to me they imply that the situation isn't "perfectly good." Instead they give me (native Am. English speaker) the impression that the situation is actually fairly bad, but any attempt to intervene is likely to make things worse
    – BThompson
    Commented Aug 4, 2021 at 15:14
  • @BThompson That's fair enough, I agree. Commented Aug 4, 2021 at 20:17
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    Often heard in the form "Let well alone".
    – nigel222
    Commented Aug 5, 2021 at 10:00
  • ''Let sleeping dogs lie'' sounds slightly literary and probably wouldn't be heard in everyday speech (at least not where I'm fron). Commented Aug 5, 2021 at 12:25
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    @EllieK I generally agree that well enough and perfectly good are quite close in meaning; however, I don't parse "Leave well enough alone" as describing the situation as "well enough". I see it as describing the manner in which the speaker wants the listener to leave the situation alone. Again this implies (to me) that the situation is not good, and involving oneself is only likely to make things worse and/or drag the listener into a bad situation they needn't be part of
    – BThompson
    Commented Aug 5, 2021 at 16:07

The expression "gilding the lily" means to add needless changes to something that's already of high value or near-perfect. So "don't gild the lily" would perhaps covey what you're looking for.

Or, "don't wreck a good thing" might fit, if the proposed changes were obviously going to lower its value. But this is very commonly used in cases where people are benefiting from a system which is non-standard or sub-optimal. Like if you found you were undercharged for a retail good, and were proposing to bring the error to the shop's attention so they could charge you the correct higher value, a friend might say "don't wreck a good thing". So similar in intent but perhaps not exactly what you're describing.

I'd go with "don't gild the lily".

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    To me, "gild the lily" has a connotation of overdoing it — i.e. trying to add extra, unneeded embellishments that actually make it worse. Commented Aug 4, 2021 at 16:31
  • @anotherdave Yes, quite right. I think I was really looking at the stress the OP was putting on the thing being "perfectly good" to begin with, even for changes that are nominally (or superficially) improvements.
    – CCTO
    Commented Aug 4, 2021 at 18:58
  • yeah it's definitely a valid option (depending on the angle the OP is going for), was just adding for extra info Commented Aug 4, 2021 at 20:05
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    Except that "gilding the lily" is a re-wording of the original: "To gild refined gold, to paint the lily, To throw a perfume on the violet, To smooth the ice, or add another hue Unto the rainbow..." (Shakespeare, "King John", Act 4, scene 1) It changes the entire meaning, which was that those acts are not only unnecessary, but pointless. While a gilded lily might be rather fashionable among certain florist circles :-)
    – jamesqf
    Commented Aug 5, 2021 at 0:33
  • No, that's a totally different context and meaning. Commented Aug 5, 2021 at 23:38

Here are two other proverbs that mean the same thing.

"Never change a running system"

"Don't change a winning team"

Also, the correct proverb is "If it ain't broke, don't fix it."

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    I'm not sure I would call those proverbs. They sound like things you might say in specific situations where "if it ain't broke..." would also apply. Commented Aug 4, 2021 at 17:09
  • The above are all proverbs according to online dictionaries. I've edited the answer to include references. Commented Aug 4, 2021 at 18:12
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    In that case, I take it back, although I'm certainly surprised. Interestingly, the first of these cross-references "don't reinvent the wheel", which I think would be a great answer to the question. Commented Aug 4, 2021 at 18:20
  • I agree. That is a great answer as well. It denotes not wasting time on improving a thing that is already perfect. Commented Aug 4, 2021 at 18:21
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    “Never change a Running system” is no proverb. It’s about not changing a computer system while it is running, but stop the system, apply changes, restart it. Like you wouldn’t change the wheels of a car while driving, even when one needs changing: You stop the car first.
    – gnasher729
    Commented Aug 5, 2021 at 16:41

If you want a lighthearted way to joke about someone trying to fix something that they should have left alone, there's

"If it ain't broke, fix it 'til it is"

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    Or often heard in engineering, "if it ain't broke, marketing haven't had their say yet".
    – Graham
    Commented Aug 4, 2021 at 17:21
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    Or some say in corporate meetings, "If it ain't broke, break it to pass the time." Commented Aug 4, 2021 at 18:20
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    Another variation: If it ain't broke, it doesn't have enough features. Commented Aug 5, 2021 at 20:28
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    @SyedDanishAnwar haha nice Commented Aug 5, 2021 at 23:40
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    Ha. My wife bought me a T-shirt with "Engineer's Motto: If it ain't broke, pull it apart and fix it." Knows me too well.
    – throx
    Commented Aug 6, 2021 at 2:33

"Don't reinvent the wheel"

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    That has a different meaning. To me, it means, if you have something that's working, don't try to come up with another way to get things working. If you're working in your yard moving earth using a wheel-barrow and your spouse suggests using a wagon instead, he/she's "re-inventing the wheel" (not a great example, but it does involve wheels).
    – Flydog57
    Commented Aug 4, 2021 at 22:22
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    In my experience, "reinventing the wheel" is said more about situations where your problem has a well-known standard solution, but you aren't aware of that solution so you try to come up with your own instead. The idea is that you should start by investigating existing approaches to a problem, rather than assume there are none.
    – kaya3
    Commented Aug 5, 2021 at 17:52
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    To the previous two commenters: the question was about a phrase that means “not to change a perfectly good thing”. You’ve both described situations that fit this perfectly. I think “don’t reinvent the wheel” is a great answer. Commented Aug 8, 2021 at 8:17

"The great is the enemy of the good."

When you have something that is good enough, do not risk making it worse, just because you are tempted to try to make it great.

Variations are often seen, such as, "The perfect is the enemy of the good." See also: https://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good

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    I’ve always heard this as, “The perfect is the enemy of the good.”
    – Davislor
    Commented Aug 4, 2021 at 19:35
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    Often abused as “we can’t have the perfect, therefore we don’t even try to get the good” and rather continue using something bad. Say we have A which is really bad. C would be perfect but is difficult or expensive or both. Therefore we can’t get B which is cheap and much better than A but not perfect.
    – gnasher729
    Commented Aug 5, 2021 at 16:44

Don't change horses in midstream is another one. Sometimes seen as "swap" instead of "change", or "midrace" instead of "midstream".

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    I believe that the proverb means not changing position when part way through a project or campaign. Commented Aug 4, 2021 at 18:18
  • @SyedDanishAnwar It does perhaps imply a timeframe, i.e. after the "stream", you can then feel free to "change horses". But it's at least a related concept, worth considering. Don't know the exact context the OP is looking for. Commented Aug 4, 2021 at 18:41
  • Agree this says more about when to change rather than what to change. Whether or not the horse you're riding is any good, you should not change it in the middle of a stream. It doesn't imply that the horse you're on is good in any way, nor does it suggest that you wouldn't be better off with a different horse - just that you shouldn't change at a particular time. Commented Aug 5, 2021 at 15:50

"Don't mess with success"

"Don’t mess with success” is another way of saying “if it ain’t broke, don’t fix it.” “And I might say you don’t mess with success” was cited in print in 1964. It does not appear that any one person coined or popularized the simple rhyme.



"Never change a winning team"

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    Hello, and welcome to the ELL. Your answer could be improved by providing references. See tour.
    – fev
    Commented Aug 5, 2021 at 8:50

An algorithmic-focused answer:

Premature optimization is the root of all evil.

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    No. That means “don’t try to improve something until you understand it well enough to be sure that your changes will be an improvement, and that you can’t achieve a much bigger improvement if you gain more understanding”.
    – gnasher729
    Commented Aug 5, 2021 at 16:47

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