Replaced iPhone Battery

I ordered a replacement battery for my 3 year old iPhone 3G a few months ago from http://www.ifixit.com/ and finally got around to replacing it this weekend. I tried to swap it from a remote location with only the tools provided in the iFixit kit http://www.ifixit.com/Guide/Repair/Installing-iPhone-3G-Battery/577/1 but the screwdriver was too narrow to replace two of the screws, so I had to wait to get back to my desk and try again with eyeglass screwdrivers and it worked! The project took about 25 minutes and now my new battery is charging... Curious to see how long it will last in comparison.