Iphone 4G original battery only lasting half a day on a full charge.
The battery replacement took 5 mintues start to finish using the pentalobe screw replacement kit, plastic tools and replacement battery. My battery was practically cemented in place from the sticky stuff they put behind it, so -per the ifixit video- the plastic pry tools were invaluable. Once the battery was GENTLY pried loose, the replacement went in no problem. Phone works great now!!!
Definitely watch the short video (which I did)!