20 - 30 minutos
My wife's phone was running out of juice twice or three times a day.
The instructions were clear and the battery looked and acts identically to the factory unit. The install was easy and complicated only by the fact that she'd had her screen replaced a few months ago so it wasn't glued in the factory-standard way. Also, the plastic spudgers, though fairly effective, broke when trying to pry the old battery loose. I was able to complete the repair with a standard small flathead screwdriver, though, and it's running as good as new.
None needed, it's as easy as it appeared in the installation guide. Just take it slow & steady and it'll be done in a jiffy.