The battery was not holding a charge very long.
I ordered the battery for my iPhone 4 and it arrived in two days – which was awesome. It took me about 10 minutes to replace the battery. I took out the two Pentalobe screws at the base of the phone using the supplied Pentalobe screw driver and slipped up the back of the phone and removed it. I removed the Phillips screw holding in the battery contact using the supplied Phillips screw driver and pried up the contact. I pried out the battery, which was glued in pretty well, using the supplied tool. I then connected the new battery contact to the phone and reinstalled the Phillips screw. I then replaced the battery and closed the back of the phone with the two Liberator Phillips screws. The most time consuming part of the operation was prying out the old battery. The new battery had a 45% charge which I ran down to 10% and then recharged to 100%. The phone is holding a charge much longer now. This was a very easy and inexpensive way to fix the iPhone. Btw – I’m 68 and had no problems replacing the battery at all. Thanks Ifixit.
Anyone with an aging battery should definitely consider replacing it with a battery from Ifixit.