My rides usually go out into the desert mountains for a full day, sometimes on well-graded gravel, so I often carry lunch and extra water along with the seat bag holding regular tools, spare, and puncture repair. Two water bottles and a pump are on the frame. In monsoon season I'll bring a rain jacket, rain goggles, and extra jersey. I have a rear rack and sometimes put a single rear pannier on it, if it's cumbersome to strap the load to the top. Sometimes I bring a book and take a long break under a big juniper or mesquite. Most rides I combine with a shopping trip and will stop for groceries or supplies on the way home, so a small cable lock comes with, too. I don't own a cell phone (no coverage many places, anyway) and try to be self-sufficient out there.