Not too often, I'm not a moody person.
depends on the day.
I have never kept track
It varies...I can go from "Oh I love the world" to "I am about to punch someone in the face" about 20 times a day
My mood generally doesn't change more than once per day. If I am in a good mood it will last most of the day. If I am in a bad mood, it will last all day, sometimes punctuated with humour