The battery on my iPhone 6 would no longer hold a charge. Sometimes, I'd be using it and it would say 30% but then suddenly just shut down. It had become unusable.
Perfect. The only snag was pulling out the adhesive. The tabs break off very easily.
Be careful reconnecting the cables. Don't reattach all those tiny screws in until you've tested to make sure all the cables are seated properly. Also, be very careful pulling the adhesive out. Those tabs break pull off very easily.