I carried a penknife in my pocket from the time I was about five until after I graduated from college. Then I stopped carrying one regularly because I found it was wearing holes in my pockets.
I got my first penknife by sending away for it with an offer from a box of cereal. My parents tried to divert it when it arrived in the mail, but I soon discovered that it had arrived and insisted on having it. I still have a small scar on my hand from where I cut myself with it the first time I tried it out, but I'm glad to say my parents let me keep it.
I was 10, and saved up for almost a year to get a Swiss Army Knife. My parents told me I was wasting my money and would just lose it. I carried it for 40 years, and the plastic handle wore off. I now carry the replacement.
I went to an amusement park last summer. They used metal detectors going in and wanted to take my knife away. I guess they feared I would hijack a roller coaster and crash it into a skyscraper. I turned back and went home.