all hours

Irregular times, as in You can't come home at all hours and expect your supper to be ready. The expression can also mean “late at night,” as in College students like to stay up talking until all hours. It is sometimes amplified into all hours of the day and night. [c. 1930]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.