Simple swap with a bit of elbow grease and Youtube help
Shun Chu -
The original batteries in the late 2013 MBP was bulging. It was their time to retire. :(
The repair went smoothly without any snags... but only with the help of an external source. Methods described on the iFixIt tutorial was simply way too complicated and would actually introduce more complications than necessary. And they'd also take way longer to perform. However, I did purchase the batteries and the tool kit from iFixIt to perform the swap.
Two points to make for swapping out batteries on this model:
1. Get the tool kit and battery pack from iFixIt (whatever premium they charge for it, they've done the homework on what to use... it'd save you a ton of time to research it on your own and risk incompatibility issues)
2. Instead of following the complicated instructions on iFixIt, follow the methods described in this Youtube video: https://www.youtube.com/watch?v=rfHHIERH...
Besides that, I can't say enough good things about the quality of the tool kit and battery pack from my purchase!