The top corner of my screen cracked a whole hour after I took my case off, so I decided to get in touch with my iFixit friends to get it repaired. While I was doing that, I decided to replace the battery as well.
It was a piece of cake! The Repair Kit had everything I needed, and was labeled perfectly. It aligned perfectly with the manual, and I knew exactly which tool I needed every step of the way. The high-quality, zoomed in photos of each step helped reassure me when I didn't think I was removing the right part, or something wasn't disconnecting. I never even needed to watch any videos, the manual led me every step of the way! All-in-all, it took me about two hours to remove the screen and battery and to replace it with my new parts.
I have a newfound appreciation for my phone now, and feel like we've been through so much together! It sorta feels like after you get a carwash, when you're extra careful not to drag in any dirt or smudge the windows. I bought a screen protector as well, and honestly I feel like I bought a brand new phone for less than a hundred bucks. Stoked!
Following the instructions precisely will probably help avoid having any issues with the reassembly. Any time I felt like something didn't "pop" in correctly or wasn't flush with the rest of the parts, I would refer back to the manual and check the photos.
It also helps to have a piece of paper to label every screw and plate that you remove in order to avoid putting something back in the wrong place.