Day in day out every day without fail phrase.
"Day in, day out, every day without fail" means something that happens on a daily basis
She is so devoted to music that she practices singing and playing musical instruments day in, day out, every day without fail after school
My brother is a soldier who wakes up at 5 am and does physical exercise day in, day out, every day without fail.
I go to school late, day in, day out, every day without fail.
Very frequently and predictably.
This phrase is used based on its literal meaning.