I found the same thing. If you dry your blades after using it will really extend their life. I hear that alcohol helps too.
I throw my doubles out after 2 shaves, but then again they're really cheap..
Nick:Personna's here.. The price is right and even though they're the only ones I've tried, they work well enough that I have stocked up on them.. The walmart cashier looked at me suspiciously when I checked out 10 boxes of them I have a tendency to hoard consumables...