5 - 30 minutes
Blinking ? Thought it was the hard drive. It's got to last one more year. Plugged in a bootable backup but couldn't see the hard drive to repair or diagnose so decided to replace it. Turns out it was the Hard Drive Cable. Works fine now and I have a spare Hard Drive just in case.
Went pretty well. I had most of the tools already but good idea to buy the spudger. I used a 00 phillips to open the case. The one that most people might not have is the tiny star-shaped screwdriver to get the screws out of the side of the hard drive. It took maybe 20-30 minutes because I really took my time and checked each step to be sure I was doing it correctly. By the time I replaced the cable, it went even more quickly.
Be patient. Do unplug the battery even though it looks like an optional step. Have a safe place to set the screws and keep track of where each one was exactly. The ones on the side of the case seem a little different and go at a very slight angle. Would have been nice to have an antistatic mat but luckily I didn't fry anything this time.