My history of PSPs...
PSP 1: No longer had the ability to use the enternet so I exchanged it
Drops: 10
Time: 1 year

PSP 2: I lost a game and threw it at the ground, then the screen was perminately black, so I went outside and threw it against the cement. It's now in over 10 pieces.
Drops: 6
Time: Half a year

PSP 3: It wouldn't load games so I exchanged it.
Drops: 3
Time: 5 days

PSP 4: It's still alive.
Drops: 3