20 - 30 minutes
My old battery would lose power such that it needed to be charged more than once per day, even if it was seldom used.
The repair was very easy. I'm very pleased with the new battery, works like a new phone now! The tools provided were great - I'm especially happy that the screwdriver was magnetic - that saved a few lost screws!!
Make sure to separate the screws you take out at each step - not all screws are the same length, or the same threading. Take your time, and pay close attention to the photos provided in the guide. But for the most part, the guide was simple to follow.