I think it is well known that if we indulgently let something bad happen, there will be more similar cases arising. The outbreak of the negative effects could be unstoppable. So is there any idiom, proverb or fancy expression used to stress this point.

  • Could you please give an example sentence with some context? The correct use of idioms/sayings/fixed expressions, etc tends to depend on context.
    – Greybeard
    Feb 14, 2020 at 9:22
  • 1
    See also Letting the camel's nose get in the tent
    – Mitch
    Jun 21, 2021 at 18:59
  • What we accept, we encourage. Mar 22, 2022 at 23:07

3 Answers 3


There is

A stitch in time saves nine.


Don't spoil the ship for a ha'porth of tar.

and also

For want of a nail, the shoe was lost;
For want of the shoe, the horse was lost;
For want of the horse, the rider was lost;
For want of the rider, the battle was lost;
For want of the battle, the kingdom was lost;
And all from the want of a horseshoe nail.

There is also an expression

the thin end of the wedge

for which Merriam-Webster has

the beginning of something that will become more serious, unpleasant, etc.
The bank's decision to raise rates could be the thin end of the wedge if other banks follow along.

  • Thanks, the first one is right on point, but the second and third one is kind of off the topic, as IMO, it only strengthens the importance of attention to details or trivial stuff. What I want to promote is the point to stop making mistakes in the early stage.
    – jazelly
    Feb 14, 2020 at 9:29
  • I included the lines for interest. The "wedge" one conveys your idea of being unstoppable once it begins to happen. Feb 14, 2020 at 9:31
  • To add to the collection - "nip it in the bud"
    – user888379
    Feb 14, 2020 at 14:35
  • And didn't Rumi say if you don't want a camel in your tent, don't let him stick his nose in? Feb 14, 2020 at 14:55

A quotation sometimes attributed to Benjamin Franklin is An ounce of prevention is worth a pound of cure.


Depending on the context, this idiom might work

One rotten apple spoils the barrel

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