I now carry my digital camera with me mostly everywhere because like many amateur (and professional) photographers there are so many interesting pictures that one misses taking.
For example, when I was moving cross country a few years ago I was driving on a highway through Tennessee. There on the highway was a truck towing a flat trailer with what would you believe was on it? A crashed white airplane! This truck was towing a wrecked plane along the highway. I didn't even own my camera back then and didn't think to keep one near at hand, but I sure would have liked to have taken a photograph of that wrecked plane being towed on a highway! I hate missing the lucky interesting photo shot ops!