Okay
Generally spirits take about a month to investigate their new guests and determine if they are a threat. It is different for all spirits, though. Once that time is done, they either leave you alone, or start getting aggressive.
I'm
i'm on my bed right now
So
MY encounters have been minor
Just some small shadows appearing out of thin air and dashing across my room
BUT
My brother claims to have seen a tall, pale figure with a white dress on, at 4 A.M.