One word; Abuse. (intentional or not).There are so many people here complaining that their 2009/2010 MBPs are "on their last legs" (learning a new expression every day). How can that be if they are supposed to be of a high quality build?
"Last legs" is a relative term. To me, any Apple product that has earned this label is at least still functioning pretty much normally. I have a closet full of Dells, Toshiba's and HP's that never seemed to have any "legs" at all and died abruptly. R.I.P.
kills OSX that's the end for me. If they go ios7 way on OSX i am done guys. That's just abomination.