The battery life was very short on my wife's and my iPhone 5c.
I did my phone first, it took about an hour as I was careful not to mess up. I had a problem with the adhesive strips breaking. Thesecond phone took twenty minutes..
Get the battery removal card or have a mag stripe motel key on hand. Used a hair dryer on low to heat the back of one phone. For the second phone I bought a $7 small, reusible hot/cold pack at CVS heated according to directions in the microwave and let it sit on the back of the phone for about 2 minutes, the battery popped loose in a jiffy.