Today's "NHK buisiness English"
"day in and day out" means "day after day", but is mainly use negative means. "day after day" means over a long period, continuously or repeatedly over a long period. It is neutral.
"day in and day out" means "day after day", but is mainly use negative means. "day after day" means over a long period, continuously or repeatedly over a long period. It is neutral.