My iPhone 5s was losing its charge super fast. Good for maybe 4 hours (maybe).
The repair was harder than I expected.
In particular the glue holding the battery in place broke off and made it really hard to remove the battery.
Additionally, I damaged the display somehow during the repair. Although I followed the instructions closely, somehow the top portion of the display separated.
Once I had the phone reassembled, I couldn't get the upper corner of the display to reseat into the phone frame. Sigh. You could see light coming out of the gap between it and the phone frame.
The display continued to work. But it flexed and looked shabby.
After a couple of days I went to the Apple Store and bought an iPhone X. Awesome. Totally awesome hardware.
I suspect that over time some repairs get harder to do. Adhesives and plastic components dry out, lose flexibility, and are more likely to crack during a repair.
I got my iPhone 5s back in 2013.
4.5 years is a good run for a phone.
If you try this repair and it doesn't work... just treat yourself to a new iPhone X. Come on. You've been good. You've made that old 5 last a long time.
It's OK. Nobody is going to judge you. Go get it.