The Mongol Derby is primarily about riding- there's no point being wonderfully comfortable every night when you bed down and being able to check your horoscope on your iPad if the hassle of de-camping and keeping all your stuff attached to your horse brings you out in a rash. Think hard before you carry anything for 1000kms.
Bear in mind that stuff attached to you will be much more tiring for you than stuff attached to your horses- they are all going 40kms only, you are going 1000kms. BUT stuff attached to your horses is much more likely to gallop off into the sunset without you if you fall off. Ah, the old risk-reward conundrum again.
The only pieces of equipment you are obliged to carry are a riding hat, a water-carrying vessel, your rider card and the SPOT tracking device so that we can see where you are. You'll also need to provide your own stirrups and fenders/leathers. Other than these things, what you bring is up to you.
We've set a 5kg weight limit on equipment as we don't want the horses to be weighed down with endless bits and pieces. See the Weight Limits section of the rules for the details on this. With 7 derbies' worth of experience to draw on, we have a fair idea of what is useful, and what is not, but one man's essential is another man's paperweight, so you have to work this bit out for yourself.