Consistency means having predictable and unchanging behavioral expectations and predictable and unchanging responses to undesirable and unacceptable behavior. It means meaning what you say and saying what you mean and following through even when doing so is not convenient.
For children to understand that the expectations and rules are not arbitrary they must be consistently enforced. This means that children should be consistently held accountable to the expectations and rules that are established by enforcing consistent consequences. If a rule has been broken, the set consequence for breaking that rule should be enforced. If an expectation hasn’t been met, a child should be reminded of what the expectation is.
If a rule needs to be changed, it should be changed before it is next broken. As children grow and mature, the rules, behavioral expectations and limits should change and grow with them. An older child will naturally have different rules, behavioral expectations and limits than a younger child. For example, a school aged child can be expected to enter a store and not touch the items on the shelves, while that expectation would be inappropriate for a toddler.