1 - 2 hours
I needed more ram than my original 8 gb and wanted to stick in two 8 gb ram sticks
The repair went great except for the fact that I didn't thoroughly plug in my screen and speaker connections.
Check your connections before you tape the screen or it might go wrong and you'll have to reopen the screen
Heavy-Duty Suction Cups (Pair)
iFixit Opening Picks (Set of 6)
iMac Intel 21.5" (2012-2017) Adhesive Strips