Children, because they are normal human beings, resent being told what to do and when to do it.
Every family needs an objective, non-partisan referee for daily events.
The kitchen timer can be just that. A kitchen timer is one of the most useful tools a parent can own. Take the timer out of the kitchen. With young children, the timer makes a great game. Children love to race the bell and quickly learn how good it feels to be cooperative and gain a parent's positive attention.