For me, it's not the miles, it's the time. If I'm riding on the road, I take some Hammergel and a packet of Luna Moons, an energy/protein bar and a banana. I may not eat it all, but I do take in some gel every half hr or so, just a squirt. After about 1.5 hrs, i will stop for the bar or banana, and a couple Moons. After another 1~1.5 hours, I will stop again and have what I did not eat before, either the bar or the banana. If I am on my mountain bike ride, and am not near any store, I will take a sandwich, either a PBJ or (don't laugh) corned beef on rye or similar if the ride is more than about 2.5 hours. For shorter MTB rides, I will take the banana/bar/gel/Moon combo. I like to stop somewhere quiet on the MTB and rest for a short while and enjoy my lunch; I'm not out to hammerfest myself silly on the road or in the dirt; I want to enjoy the time and the refuel just makes me feel better.

But each person is different, what I can tolerate on the ride (corned beef) may not sit well with someone else. I've seen people take out an orange, which might sound refreshing, but if I ate it I would have instant heartburn that would last the rest of the ride.