Dispose your subscriptions

Lifetime management

this.WhenActivated(
    disposables =>
    {
        this.WhenAnyValue(...)
            .DisposeWith(disposables);
    });

See also when activated

Not all subscriptions need to be disposed. It's like events. If a component exposes an event and also subscribes to it itself, it doesn't need to unsubscribe. That's because the subscription is manifested as the component having a reference to itself. Same is true with Rx. If you're a VM and you e.g. WhenAnyValue against your own property, there's no need to clean that up because that is manifested as the VM having a reference to itself.