When riding alone, I stop when I feel like it. Sometimes I feel strong and, if there are no features worth seeing or photographing, I can ride for up to two hours. I drink frequently, on the fly. I don't need a schedule, my body tells me what I should do.
The danger is when I ride with someone who is stronger than I. It is important to go at your own pace, and if I try to keep up, thats when I can get into trouble.