For kids with adoption related struggles, I think in some ways this is even more true. Because so much of adoption issues revolve around a child's status quo being turned over, where a parent is saying "I love you too much to let you stay this way." That has to create conflict and chaos not because it is a battle of wills but because it is a battle for the heart of a kid. In other words, without chaos and conflict there can be no growth, no improvement, no successes.
So when weariness sets in, may we all see that weariness as our child being on the cusp of something big, that if our child can just get over the hurdle, accomplishment lies on the other side.