Rule 5 of 8 · Chapter II — State & Rendering
Dispose what you subscribe.
Why this rule exists
A component that subscribes to a service event and skips IDisposable leaks itself on every navigation. Server-side, that is a per-circuit memory leak that compounds with every user.
In practice
Any += in a component demands @implements IDisposable and a matching -= in Dispose. Code-review for the pair, not just the subscription.