Most people do not stop as often as their doctors would tell them to. For medical reasons you should stop often. (experts don't seem to agree on exactly what the right amount is, but for discussion lets call it 5 minutes out of every hour). Note that the stop is to move around, if you sit on a toilet for that time it doesn't count.

Many people will stop only for fuel every 3 hours, and try to get everything they need to do (restroom, buy snacks, eat...) in the amount of time it takes the pump to fill the tank. This isn't a good idea, but it is what people in the real world do.