Bought a used iphone 5S about 10 days ago, (first smartphone for me), which had a bad battery. Using the tutorial and battery replacement kit provided here, and successfully replaced the battery, AND IT STILL WORKS!! First time ever working on a phone. I did have the adhesive strips break immediately and had to use a heated wet towel in a plastic bag to heat/loosen the battery, then pry the battery out. I was terrified I might rupture the battery, but I didn't! I also used several of the suggestions to keep from damaging the home button cord, using tie strap to keep from opening too far and then sliding cover to side rather than lifting to gain access. I also did not disconnect anything but the battery. Instead, I tied the front of the phone to a heavy food can while I worked on removing and reinstalling the battery. Took 25 minutes, start to finish!

Thank you IFIXIT!!!

a 61 year old ER nurse...lol