keep (some kind of) hours
1. To maintain a particular pattern or schedule of being awake and asleep. Because of the huge time difference, Sam has kept really strange hours since coming back from Japan. It's important that the kids start keeping regular hours when they are young, since having unpredictable bedtimes can cause a lot of problems with sleep.
2. To maintain particular business hours. The local doctor has always kept rather irregular hours. Sometimes it just comes down to luck whether he'll be there at all on a given day.
keep... ˈhoursif you keep regular, strange, etc. hours, the times at which you do things, especially getting up or going to bed, are regular, strange, etc: Keeping irregular hours is hard on children, so try to set a regular bedtime and a regular time to get up.
See also: hour