How often do you think about your own death?

I just wonder.
A few days ago I talked to tribun about it and I said I think about my own death quite often. In the sense of... imaging how I could die in this particular moment. So, it often happens when I am on my way to work or home, because I my mind likes to wander when I am riding my bike.
I don't think about these things with fear. It's more a checking of the possibilities.
Well, talking about it I asked him how often he thinks about it and he said (as far as I remember), about once a week andsaid that is often. I told him I think about it nearly every day. Maybe even twirce. I just imagine to be hit by a car or how I could slip and fall down the roof or so. It's never about suicide or something! I can't say I enjoy this and as I said I don't fear anything either. They are just plain thoughts like... don't know.
Can't tell you why I do this.