I always carry a knife with my keys and hardly any change in my pocket anymore. I can't remember when I started carrying. It had to be very early in elementary and possibly even in Kindergarten.
ANY working guy has a knife on him. No matter what, I have a Shrade Old Timer Papa Bear (the biggest folding lock blade they make) on me at all times, wedged in the corner of my right rear pocket... It fits right alongside my wallet, and the wallet works to keep it upright and easy to get at.
I also always carry my sliver-gitter - A wicked sharp little 3 blade ranch style pen knife in my right front pocket. And normally, a leatherman is on my belt, and if I am out in the woods or pastures, and for sure if I am walking off, there's a big-ass bowie hanging on my belt too, along with a bushcraft/camp/companion knife...
I know there is an 'armed' component - I know I am armed. And I would not hesitate a minute to draw a knife in defense. But that's not what them knives are about. In the main, they are just tools that I need on me every day. And there is not a day, hardly ever, that I don't use them.
I can't imagine a world where a man is without a knife. Cannot even fathom it.