In the case of an ordinary delayed service component, SCR immediately deactivates and destroys the component when its service is released by the consumer. In cases where a consumer occasionally binds and invokes the service (e.g. EventAdmin) this can cause the component to be continuously destroyed and recreated.
Note that Equinox's DS offers a little more control, we can choose either to immediately clean up or never clean up (and the default is never). This is still not very satisfactory though.
I think ideally there should be a configurable timeout, so that a component will be cleaned up only if it is not used for some time. I also think the default should be quite long, e.g. many minutes.