With the news breaking that Apple is purposefully slowing down iPhones with worn-down batteries, I decided to go ahead and have the battery on my iPhone 6s replaced yesterday. One day in and I’m already amazed at the difference it makes. The proof is anecdotal, but starting up Flitsmeister – a must-have speedtrap app for my daily commute – for example, started taking a good 15 to 20 seconds after installing iOS 11. That has gone back down to 5 seconds tops after replacing the battery. If you still want to wring some life out of your older iPhone, definitely consider going this route.
On a related note; my iPhone 6s is actually eligible for a free battery replacement program from Apple, but the hoops they make you jump through to get that battery are maddening and in the end I figured paying a third party was faster and easier. Making an appointment to get the phone looked at by an authorized service provider took ages. Splotches on the side of the screen were considered signs of water damage (its never touched water in its life); a slight bend in the case meant I must wear the phone in my back pocket and sit on it (I don’t), both of which might invalidate my eligibility. If you don’t want to replace these batteries, Apple, don’t do a fucking program.