night and day

1. Also day and night. Continually, without stopping. This phrase is used either literally, as in The alarm is on night and day, or hyperbolically, as in We were working day and night on these drawings. Shakespeare put it by night and day in The Comedy of Errors (4:2): “Time comes stealing on by night and day.”

Example Sentences

“Going from high school water polo to the junior level is like night and day,” he said.

From Los Angeles Times

“I feel like it’s night and day,” he said when asked to describe the biggest difference in himself from Year 1.

From Los Angeles Times

"I wasn't well. I was in so much pain. Today it's night and day how much better I felt," Williams said.

From BBC

“So his attitude now — it’s night and day.”

From Los Angeles Times

She said staff had been "working night and day" to ensure the appeal was robust.

From BBC