I know for sure that mine has hardly ever left the slot but I did notice that I had intermittent problems with it just before it died.
Considering that I've never had any other cards die (CF, SC or XD), I'm pretty appalled. I'm now starting to think that they've skimped on durability for the MicroSD format. What's the point in having such a small card on a phone anyway? MiniSD was fine, right?
Oh well... must stop ranting