When subscribing to an observable in a component, you almost always arrange to unsubscribe when the component is destroyed.
There are a few exceptional observables where this is not necessary. The
ActivatedRoute observables are among the exceptions.
The
ActivatedRoute and its observables are insulated from the
Router itself. The
Router destroys a routed component when it is no longer needed and the injected
ActivatedRoute dies with it.