20 - 30 minuten
My iPhone 3GS is about 4 Years old now and the battery needed to be replaced. Therefore I bought one not to cheap replacement battery at ebay. It works for about 1 year, then it was at the end of its life again. The next battery I also bought at ebay, but this one had so bad quality, it only lasted for a few minutes. Finally I decided to by a replacement battery at ifixit, because a German blogger had written a good review for their batteries.
And this battery is top! The iPhone now lasts for more than 1 week in standby, of course without any use of it. I´m having a newer iPhone 4, but I want my first iPhone 3GS to be kept alive at any time for any purpose. Maybe my iPhone 4 is broken sometimes in future?
The replacement was quiet easy - I did it more than 4 times before with the ifixit photo documentation. All you need are the small tools (inside the replacement kit), a clean desk and 30 minutes without disturbance.
Take care not to mix up the screws - they have different length! And don´t by any of those "original replacement batteries" at ebay or somewhere else in the internet. Those batteries are all fake, not original. Only the ifixit replacement batteries are good.
By the way: I´m from Germany, and the shipping to Germany didn´t take longer than 8 days. Perfect!