How do you reduce widget rebuild?

You rebuild widgets when the state changes. This is normal and desirable because it allows the user to see the state changes reflected in the UI. However, rebuilding parts of the UI that don’t need to change is wasteful.

There are several things you can do to reduce unnecessary widget rebuilding.

* The first is to refactor a large widget tree into smaller individual widgets, each with its build method.

* Whenever possible, use the const constructor, because this will tell Flutter that it doesn't need to rebuild the widget.

* Keep the subtree of a stateful widget as small as possible. If a stateful widget needs to have a widget subtree under it, create a custom widget for the stateful widget and give it a child parameter.