I live in the city and carry a knife where allowed. I use it to open boxes and packaging, cut food, turn screws (sometimes when they fit), pry things open, pick out splinters, strip wires... Its the most basic tool.

The other day I was replacing my windshield wiper blades and needed to pry out a small adapter that they came with and used an old knife I keep in my car. I was doing this in the parking lot of the auto parts store because the first set I took home did not fit correctly even though the computer said they did.