I have a MBP 13" from 2009 (5,5).
I use it a lot, it's on most of the time (but not all the time).
An apple care employee told me he hasn't seen many hard-disk failures, but isn't it the first piece of hardware which is supposed to fail ?
I did a hard-disk verify, told me I should do a disk repair (red error message), disk repair told me all is fine, and now it doesn't boot, or take ages to do so.
I have been taking great care of it, all in all my MBP fell once, from a small height. Isn't the hard disk the first thing to suffer from falling ? How resilient a laptop motherboard is against shock versus a hard-disk ?