iPhone 4 (Verizon) Battery was a year old, was facing problems with it
15 - 45 minutes
Wasn't taking a charge at times and the battery was dying at a rapid rate.
it went well, Though my liberation kit was messed up and i ended up putting the original screw back in, i think the screwdriver sent with the kit was too big or maybe it was human error but didn't put use to the kit.
Follow the guides they help if your not tech savvy but if you know what your doing like myself, then IFIXit has a great product and im happy with my purchase for the most part.