10 - 30 minuten
The OEM battery, which was 3.5 years old, had lost the majority of its capacity and was becoming exceedingly unreliable. The phone had been working well otherwise (on iOS 8.4.1), and I wasn't going to pay $80 and surrender my device for a week when I could do the work myself at a fraction of the cost.
Everything went as well as I could have imagined. Studying online guides, laying out your equipment, and general preparation beforehand will save a great deal of time and anxiety.
I do not endorse the company or any links associated with the video, but this is far and away the best pictorial guide for replacing the battery: https://www.youtube.com/watch?v=nYYdbk3U....
-Wear protective gloves (latex or non-latex OK, to keep oils and grime off of the components).
-Obtain a pair of fine-tipped tweezers; they're invaluable for grabbing and steadying screws, as well as (re)positioning the pressure contact/antenna shield.
-Work in a pan, box top, or something with a flap bottom and low sides to ensure that the screws and other pieces don't escape during the repair.