5 - 30 minutos
my battery was not lasting the day. so i need a new battery. had an iphone 4 for about two years now.
the repair was easy. happy for the warning about the amount of glue apple put on some battery, i had to work hard to remove my battery because of all the glue. otherwise, everything went fine.thanks for the great step by step guide.
Just be careful with the amount of glue on the battery, take it easy when taking it off.