5 - 30 minuten
Battery seemed to require too-frequent recharge.
Replacement procedure was exactly as explained and executed in the video tutorial. Included ifixit screwdrivers and plastic prying tools were necessary and adequate for the task. The emphasis on strong adhesive on the battery and need for plastic (not metal) prying tool was helpful.
Know in advance what you're doing. On the advice of a prior successful ifixit customer turn on airplane mode and turn the phone completely off. After replacing the battery turn on phone, wait for normal bootup, turn airplane mode off. I did that and the phone returned to normal operation without a problem. I am 65 and found that a workbench 2X magnifier lamp was invaluable for the task; a headband magnifier will accomplish the same. The potential for 'rounding' the phillips head screw that holds the battery connector to the board is good, so be careful. The screw was stubborn, but with steady pressure the screw released and backed out, but not before I slightly 'rounded' the slots. It would be beneficial if ifixit included a spare phillips screw that holds the battery connector to the board in the event the phillips slots are damaged on extraction.