Background Someday when I joint in an open discussion with a group of friends, I asked them the question about how often they are change their bank account PIN. I asked them in certain period start from 1 months, a quarter then in 1 year, less than 3 person raise their hands. Then I asked them again about did they already change their bank account PIN since they open their account for the first time. Parallel with previous question, less than 3 person raise their hands. Surprisingly that's the fact!