With all the dirt on Trump coming out recently, it seems reasonable to assume that there's more yet to come. When will this happen?
Next shoe to drop will be two days before the next debate, right on schedule. Almost certainly a verifiably true Trump assault victim, with witnesses and potentially even evidence. That or some Trump deposition tapes, Howard Stern audio, leaked security camera footage from behind the scenes at a beauty pageant or the Apprentice, something showing this kind of behavior by Trump in a clear and undeniable way.
After that and the debate has had time to blow over, Hillary will drop the nuke sometime around Halloween.