What happens if you don't unsubscribe from subscriptions?

If you don't unsubscribe from subscriptions (Observable.subscribe) in Angular:

1. Memory leaks

• Subscriptions keep existing even after the component is destroyed.
• This keeps objects in memory, increasing memory consumption over time.

2. Unnecessary calls and events

• Code tied to the subscription keeps running even though the component has already been removed.
• It can cause errors if it tries to access a DOM element or component variable that no longer exists.

3. Unstable application behavior

• Many active subscriptions can cause duplicated actions, unexpected renders, and slower performance.

Conclusion: you should always unsubscribe in ngOnDestroy() or use constructs like takeUntil, AsyncPipe, or Subscription.add/unsubscribe to avoid leaks and bugs.