I've not read of such a thing happening. My phone is a little over a year old, and a fair few people here have older ones, and they all seem to be working still.
The most serious systematic fault I'm aware of is that some of the early ones had motherboards that were prone to overheating (and hence crashing/shutting down). Anyone who had one of those should have got it replaced under warranty. Maybe that's what you'd heard of?
yes might be... btw thanx for the quick reply.