MacBook Pro mid2012 SSD upgrade WOW!
My original MacBook Pro came with 750GB HDD hard drive, after many years of outstanding use the HD began making clicking noises, apps would freeze randomly, preview images on files would not show up and single user mode fsck -fy would continue to show modified volume. Based on internet search the HD clicking noise is often referred to as the click of death.
The repair was just as the tutorial video, EASY EASY EASY. Took me approximately 10min total.
You don't even need a start up usb. Install the SSD HD, use disk utility to erase and format it on OS extended journaled, then go back to disk utility, and re-install OS X from internet, then upgrade to OS Sierra using the App Store. Very simple.
I am so amazed with this apple MacBook Pro, IMO it blows away the new ones out of the water in terms of performance i7core, 8GB RAM, and now that I installed at 1TB SSD HD its AMAZING!! I would highly recommend anyone to not even waiting, upgrade and use the old HDD if its good as a backup storage drive. The performance in speed, reliability is at another level.