After 15 months of ownership and 26.5K miles, I'm still on my original set. The trick? Well, I don't know if this is beneath any of you, but I had the same problem others reported with the wiper part of the rubber coming free from the base part of the blade. Makes no sense, the blade was fine... ...anyway, some contact cement took care of it.
Did one, 10,000 miles later the same thing happened to the driver s side wiper, so I hit that one with contact cement as well. They're both holding fine and work great....after all, they're $72 wiper blades, right?

(plus the $3 for a can of contact cement)