See the survival tip on drying out gear. Usually I concentrate my photography on the golden moments just after the sun rises and before it sets, and use the rest of the time to scout sites or travel. Film left in a hot place will deteriorate. If you must take shots during the midday glare, use a fill flash to soften shadows. This is particularly important in countries where the people wear large overhanging hats.
Filters help too.
Always bring a dry bag or some other way to keep your camera dry and out of the dust. If you must have your camera repaired in a third world country, do it in a reputable place. Then check the innards to make sure they are the same as the ones the camera had when you handed it in. Cameras and passports are the two hottest items for theft. Check expiration dates on film before buying.