This site seems to prove that Daemons are easily banished. So it would seem that they are not much of a threat. I haven't heard of anyone being drastically upset by those that have posted here. All is well.
Strangely, I have been affected by a demon over the net... It completely drained my energy. But I found a way to pull it out.
Demons vary in intensity. Ive never been fortunate enough to get a break from the really bad ones though. Once I believe I was attacked by 'the Devil', or something like it. The only thing that had saved me was the name of God. I declared "I dont fear, God protect me" and it stopped sharply. But the experience was truly terrifying.