My MacBook battery's health was down to about 60%, making it less convenient to take my MacBook to my favorite coffee shop. It was time to remedy that.
At one point, I had the right-sized Torx and pentalobe drivers to do this repair, but through various relocations of my household, they've gone missing. I purchased replacements along with the battery, and actually liked them better than the ones I used to have. Some tool manufacturers seem to believe that smaller tool sizes require smaller handles, but the truth is that my hands don't shrink or grow to match the size of the screws I'm removing - but I digress. I uploaded the iFixit repair guide to my phone, and used it during the fast and easy repair. From placing the MacBook on my dining room table to putting the last screw back into the case, I was done in about 10 minutes. The new battery had a 79% charge and a manufacture date of Dec 8, 2017, making it only about 7 weeks old at the time of installation.
I saved a decent amount by doing this myself - about $50 - but the most important thing was that my MacBook didn't have to sit in a repair shop for an entire day while they did the job. My thanks to iFixit and to Walter Galan, who authored the easy-to-use repair guide.
Don't lose any screws. A lot of them are tiny.