Also: Day in, day out
Meaning of Idiom ‘Day In and Day Out’
When something is day in and day out, it is happening repeatedly over time; occurring every day; continuous. 1Ayto, John. Oxford Dictionary of English Idioms. Oxford: Oxford U, 2010,2Ammer, Christine. American Heritage Dictionary of Idioms. Boston: Houghton Mifflin Harcourt, 2013.
Usage
This idiom is commonly used to express boredom from doing something over a long period of time, on a daily basis. It can also be used to express incredulity such as “I can’t believe you can eat the same thing for breakfast day in and day out! Don’t you ever want something different?”

Examples Of Use
“I’m tired of the same routine day in and day out. I need a long vacation.”
“He wore the same clothing day in, day out, for years. He had twenty shirts that were exactly the same.”
Origin
Used since at least early 1800s.
More Idioms Starting with D
More Day Idioms
- Even a Broken Clock Is Right Twice a Day
- Happy as the Day is Long
- Broad Daylight, in
- Back in the Day
- Red Letter Day
More In Idioms
More Out Idioms
