A fuel pump is a wear item. I've never found any rhyme or reason to it. I drove a 3rd gen firebird for 150,000 miles after I picked it up with 80,000 miles (so 230,000 miles on the car) - and never replaced the fuel pump. I was delivering pizza in it for a good couple years - so we're talking:
1. Wake up
2. Car is on fumes - get a couple bucks on the way to the pizza shop
3. deliver 8 orders - get $5 more -
4. deliver 5 more orders - get $5 more, etc
Never had that one die. My GF on the other hand - Her 3rd gen camaro had 2 of em die. She never knew how much gas was in it (sending unit failed after first FP replacement) - so she always kept it full.
Go figure. I've always heard about keeping it 1/4 full for the FP - but really they can fail for any reason at any time.