5 - 30 Minuten
My wife upgraded and I took over her 2 yr old iPhone4. The battery would last about 60 percent of the day before needing a recharge.
I went very well. The new battery went right in. I charged to 100% capacity and was blown away by how much battery life I now have. From 6am until 9pm I was still showing 38% battery life with regular usage! Wow, what a bonus.
The ONLY thing I would change is the video depicting how to lift the battery connector. The user can easily separate (break) the ribbon contacts (which I did on the old battery). I tried not to place it too far underneath as not to come in tact with the connector platform. In doing so, the metal plate pulled away the top layer of the ribbon cable. I was able to fix that by placing a small piece of dense foam on top of the plate then covering it up until my replacement battery arrived.
This is a MUST upgrade for anyone who's using a phone that is out of contract. You won't regret it.