When I was a teenager growing up in Maine, I worked at a bike shop. I rode my Raleigh Grand Prix all over Hell and Creation, and never carried a thing with me. My girlfriend's house was five miles away, and used to ride there daily. I don't remember ever having a flat back then! Of course, I'm probably jinxing myself for the rest of my life just uttering that now, but wth.

Nowadays I have a saddlebag with tools, patches, etc, on every bike in my stable.