为什么我应该在应用程序退出之前释放（因此dealloc）对象？

There are plenty of objects in each iPhone app witch will live forever till app dies. They are: application delegate, window, main view controller, may be navigation or tab controller, all the objects within them. Why on Earth should I release them just before quit spending precious CPU cycles? As far as I understand, apps process will be terminated, so it's heap, consistent or not will be gone too.There are plenty of objects in each iPhone app