A Prop, Lantern & Fingernails - Three Things You May Not Know You Need
Hard drive in an iMac 21.5" was failing so needed to replace the hard drive for continued use of the machine.
It was smooth for most part outside of a couple of annoyances (detailed in the "Enlightenment section). Had it not been for the lack of connector puller/long fingernails and magnets near the screw holes, I would've saved myself a decent amount of time on the repair.
The new hard drive booted up without issue and the steps in the guide were easy to follow.
It may have been the way I had the computer laying when doing the work but during the process of disconnecting the cables from the display, I did feel like I needed to prop the display from the motherboard while I disconnected everything. A flashlight may be needed as well if you have a poorly lit work space.
A mild aggravation when reassembling the screen was the magnets that were close to the screw holes kept "stealing" the screws away. Quick work-around was to use a thin piece of plastic between the hole and magnets.
Also, if you have short fingernails like me, you may need to look into something for the cables like the IC Extractor/Connector Puller (IC Extractor/Connector Puller I purchased one shortly after the repair). I didn't have one but felt it would've saved me about 10 minutes and been a lot safer on the components than the flat-head I had to work with.