At school, the kids run on a pretty rigid schedule. Schedules are on the board. We come in at a specific time, go home at a specific time, lunch and recess are at a....well, you get it. They are used to these routines.
If your kids really need some schedule in their lives and you need some help figuring out how to do that, look at CommonSense Media's Wide Open School. I just looked at their suggested schedules and they really aren't bad.