Is it better in general (for example) to take shorter, more frequent rests? So would a five minute rest every 45 minutes be better than a ten minute rest every 90 (say)? Is it a good idea to take more than an hour off at the half-way stage? And so on.
Any thoughts welcome and appreciated.
Consider that I am a relative novice to the long riding thing, so by all means take what I'm about to say with a pinch of salt[1].
I find that the main thing that limits how far I can go without stopping is my bladder. Having suffered greatly in the past from dehydration and heat stroke, I have a justifiable fear of not drinking enough, meaning that I end up needing to stop to pee about every 50-60km[2] (2-3 hours).
In winter I've also found I need to stop every 25-30km to wiggle my toes and get some feeling back (and even change socks on really cold rides).
Riding in Germany last month I was amusing myself by doing the maths on speeds and breaks. If I stop for 5 minutes every hour, for 12 hours, that adds up to a whole hour total, leaving 12.5 hours of the 13.5 to ride, meaning I then need to average 16kph, rather than 15. Factor in 30 mins for a meal at each of the 2 controls, and average speed needs to go up to 17.4kph... I'm not 100% sure what the best balance is in terms of rest stops to riding time, but I'm experimenting with all my rides.
The only advice I can be sure of, be careful in winter of getting too cold when you stop. If you have something insulated to stick on when you stop, do so. Keep your body heat up, if you stop for a long cafe/lunch break, consider having a clean/dry base layer in your bag that you can change into. Keep warm. With the related note of when you take your gloves off to eat, put them in your jersey to keep warm, or the sweat in there will get cold and you'll have a hell of a job getting the heat back in there...
J
[1]a slice of lemon and a shot of tequila...
[2]not as easy as you might think in a country where you can see, and be seen for miles, with foliage coverage to match the Nullarbor. Nipping behind a bush to squat down just means you're visible to a different set of people...