all hours (of the day and night)
1. A very late hour of the night or very early hour of the morning. You can't call her at all hours of the day and night—that's just rude. Johnny keeps taking the car and staying out till all hours, and I just don't know what to do anymore!
2. All day and night. Is that pharmacy open all hours? I know it's 2 AM, but I just got out of the ER and need to fill a prescription.