20 - 30 minutos
Due to the age of the iPhone 3GS battery it would no longer hold an acceptable charge, and had to be recharged several times in a normal usage day.
Read, study, and follow the on-line iFix-it directions with excellent photos and you will have your phone up and running with a new battery in just a few minutes! The iFixit battery replacement kit is an outstanding product and value!
On your first install go slow and you'll be a pro in no time at all! Make sure you have a well lit place to do the dis-assembly and re-assembly of the iPhone chassis. If the battery is stubborn about releasing from the back panel, hit it with a few seconds from a hair dryer and then re-try the gentle prying to pop it loose!