10 - 30 minuten
Girlfriend's phone was not lasting on battery power, she had to carry around a power brick for backup.
I ordered the battery repair kit from iFixit to give her as a gift before she went home for holiday. The morning of her departure she actually asked if we could go get a battery before she left!
She backed up phone via iTunes and I started scrolling through the instructions. Did my best not to touch internal components with my hands after reading warning about the oil from them potentially causing wireless interference.
Finished in less than 30 minutes. Parts and instructions were excellent. Best gift I could have gotten short of a new phone.
Prying the battery connector and battery out were probably the scariest parts. The adhesive on the battery was strong enough that I was concerned about breaking surrounding components. Gently prying in multiple positions and then using the plastic pull tab on the opposite side as prying tool did the trick.
Tucking the new battery connector ribbon in next to the battery also took some finesse. Positioning the new battery closer to the outside edge of phone helped make room for ribbon on connector side of battery.