10 - 30 minutes
Battery was getting old and weak
15 minute repair, no joke. Buy the tools, the Mac screws are so small I was afraid of stripping them.
The videos are fantastic
T5 Torx Screwdriver
P5 Pentalobe Screwdriver Retina MacBook Pro and Air
MacBook Air 13" (Mid 2010 to Early 2015) Replacement Battery