Flakey Hard Drive Replacement
The old iMac was getting flakey. Sometimes it would boot up fine, other times it would constantly freeze and pinwheel for several minutes at a time. I suspected a bad hard drive since OS reinstalls never fixed it for long.
With the new SSD, it's faster than it's ever been. I should have done this months ago.
I'm a pretty handy guy, but the tutorials for the screen removal and adhesive were a great help. Overall, it was easier than I thought it would be.
Go through the tutorials first before starting. Find all the guides that you'll need for the job. There may be more than one required.