25 minutes - 1 hour
My MacBook Pro HDD stopped responding; which was a particular problem since that was the startup disk. I tested the HDD with an external SATA-USB connector and found that it was functioning normally, pointing to a HD cable failure.
Opened up the case, followed the instructions and it went smoothly. Took me about 15minutes to swap out the HD cable and boot up.
Follow the instructions closely, use appropriate tools and keep the screws separate. Make sure you can fit the cable into the HDD enclosure before you remove the adhesive paper. Optional: If you have a 2011MBP and have not yet swapped out your HDD for an SSD, this might be a good time to do so.