usages arise from common practice
Idioms refer to people who are used to certain ways or opinions and become a kind of custom.
explain
Habit: habit. It refers to being used to a certain way of doing or opinion and becoming a custom.
source
Song Gaodeng's "collection of gaodongxi · under the cover of the Lord" said: "each can enter by means of media, flattery is soft and familiar, and it is customary for each other."
Examples
In order to return Yongle, we should respect the style of Taige, which is advocated by all the elders and accepted by all the people. (Volume 20 of shuoshishuyu by Shen Deqian in Qing Dynasty)
usages arise from common practice
Keep the profit and keep the success - chí yíng shǒu chéng
no one picks up what 's left by the wayside - dào wú shí yí
not pass on to others what one is called upon to do - dāng rén bù ràng