Calling ``++GC.Collect++`` is rarely necessary, and can significantly affect application performance. That's because it triggers a blocking operation that examines _every object in memory_ for cleanup. Further, you don't have control over when this blocking cleanup will actually run.
As a general rule, the consequences of calling this method far outweigh the benefits unless perhaps you've just triggered some event that is unique in the run of your program that caused a lot of long-lived objects to die.