5 - 30 minuten
I was unable to upgrade to OS Yosemite because of a S.M.A.R.T. error in the old hard disk.
The replacement was very easy and quick. I used the opportunity for a RAM upgrade as well. Installation of both the HD and the RAM went pretty smoothly.
I did not have to remove the battery as the guide suggested. Also, I purchased the repair kit, thinking I would need the different screw driver tips. I only needed the 00 philips, so buying the whole set was unnecessary. It would be good to mention to folks that if you never opened your laptop before there will be dirt in there that you should consider cleaning, and perhaps explain in your guide safe ways to do that. Also, was not expecting the external case for the old drive to be rubber, so had to think for a sec how to jam the old drive into it. It worked fine in the end. Did not see if you have guides for transferring data to the new drive - I had to plug my old drive via usb and start the machine with it to use it to install the new OS into the new drive, and then migrate all my old info into the new drive. Worked well in the end.