I've waited a week before voting, to think about it. If there's definitely nothing I can do, I don't want to be told until just before I'm going to notice something. For example, if I am not going to experience any symptoms at all for five years, I want four years of not knowing.
I used to be a "tell me all" person, but after some experiences with a brain tumor (DW) and bone tumor (DD), I'd do anything to avoid that experience of waking up in the morning, and suddenly remembering the bad news.
Maybe the results would be different for different scenario (more serious problem with no cure), but for me, I've learned that sometimes...
Ignorance is bliss.