You will see text like this posted on a number of enthusiast sites when discussing why fuel pumps fail, doesn't make it true however:
Fuel pumps are designed to pump fuel, not air. If your vehicle doesn't have enough gasoline, your fuel pump will be forced to pump air. If the vehicle pumps air regularly, the fuel pump will eventually fail. Your vehicle's fuel pump relies on the fuel that passes through it to provide it with lubrication and work as a coolant to keep the pump from overheating. If the pump is being starved for fuel, it stands a higher chance of overheating and burning up.
Drivers who regularly run their vehicle very low on fuel, or who periodically keep the fuel tank less than a quarter of the way full, will probably experience fuel pump failure earlier than drivers who keep a partially to fully filled tank."
"• Driving with low fuel level: Its durability depends on the lubrication and the cooling provided by the fuel. Running your vehicle on a low gas tank frequently, may heat up the fuel tank much quicker, ultimately overheating the fuel pump. As a result, due to the lack of lubrication, it becomes dry and gets damaged.
Article Source: http://EzineArticles.com/7193050"
"The largest cause of fuel pump failure is caused by the tank being run low, espesially in the winter. the pump has been installed inside the gas tank, in part, to try to keep the pump cool. when a car has been driven on a low tank, the pump will tend to get a little warm, then pumping cold gas on top of it, can sort of "shock" the pump."
"Most pumps are capable of going 100,000 miles or more, but depend on lubrication and cooling provided by the fuel itself. Frequent driving with a low fuel level may occasionally starve the pump for lubrication and cooling, which can lead to accelerated wear or even pump damage."
2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6, 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac