How to get your old iPhone battery replaced by Apple
If you have an older or heavily-used iPhone, and you're worried about Apple's admission that it slows down models with degraded batteries, here's how to get your battery swapped instead of paying for a new device.

The best scenario likely involves AppleCare+, an extended warranty available on its own or as part of the iPhone Upgrade Program. If Apple tests your iPhone and determines that its battery holds less than 80 percent of its original capacity, you're golden, since Apple will replace the battery for free. You can make this happen in person at an Apple store, or mail in your iPhone after going through an online process.
Be cautious however, especially if you choose the mail-in route. If Apple decides your battery is fine, you'll end up paying the full service fee -- plus another $6.95 for shipping if that's required.
Most other people will probably end up paying that service fee, which is $79 plus tax. Yes, even people under an iPhone's default one-year warranty, since that only covers defective batteries and not worn-out ones.
It's also possible to get repairs done through authorized service providers. Apple warns though that third parties are allowed to set their own prices, which could mean paying extra if you don't shop around.
Regardless of which route you take, note that mailing in an iPhone will probably take a little while. Once Apple receives a unit, it'll take another 3 to 5 business days to get it back. AppleCare+ subscribers do have the option of Express Replacement Service, which gets you a new iPhone right away, along with a box to ship out the old one -- but that uses up one of your two $99 "accidental damage incidents," and should you fall outside of coverage, you'll pay out-of-warranty fees ranging from $269 for an iPhone SE to $549 for an iPhone X.

The best scenario likely involves AppleCare+, an extended warranty available on its own or as part of the iPhone Upgrade Program. If Apple tests your iPhone and determines that its battery holds less than 80 percent of its original capacity, you're golden, since Apple will replace the battery for free. You can make this happen in person at an Apple store, or mail in your iPhone after going through an online process.
Be cautious however, especially if you choose the mail-in route. If Apple decides your battery is fine, you'll end up paying the full service fee -- plus another $6.95 for shipping if that's required.
Most other people will probably end up paying that service fee, which is $79 plus tax. Yes, even people under an iPhone's default one-year warranty, since that only covers defective batteries and not worn-out ones.
It's also possible to get repairs done through authorized service providers. Apple warns though that third parties are allowed to set their own prices, which could mean paying extra if you don't shop around.
Regardless of which route you take, note that mailing in an iPhone will probably take a little while. Once Apple receives a unit, it'll take another 3 to 5 business days to get it back. AppleCare+ subscribers do have the option of Express Replacement Service, which gets you a new iPhone right away, along with a box to ship out the old one -- but that uses up one of your two $99 "accidental damage incidents," and should you fall outside of coverage, you'll pay out-of-warranty fees ranging from $269 for an iPhone SE to $549 for an iPhone X.
Comments
If you want Apple to annoy you about every little change ,here & there ,you should probably use Android with a custom rom , and make your processer run at 100% all the time.
"I understand you're telling me the battery is fine. However, I would like a new one anyway, and here's my $79 for it."
This is the problem with intermittent issues - I had a problem with my mbp a couple of years ago and i just kept making appointments. In the end, they took it in to replace the part, but did such a poor job fixing it (the "repair" led to a series of successive sensor detections) they just quit the machine in the end and gave me a new one.
I can see both sides of the situation here but as a consumer it does dampen enthusiasm.
I have an old iPhone 4 which is slower than snailshit hibernating in a drawer. Rather than pay Apple an extortionate amount for a battery replacement (which they probably won't anyway in such an old phone) I could get one fitted by a local repair shop for about $20. Given that its not an "official" Apple replacement and under the impression that it will charge and discharge normally, will that battery replacement allow the phone to run at previously normal operating speeds?
As Hypoluxa pointed out above, updates could potentially spoil any chance of getting the phone to operate anywhere near as well as it previously would have. Putting an older version of the phones OS back on is not an option as, even if it were possible, newer apps wouldn't run on it.
Therein lies the "planned obsolescence".
Wadaya think?
A kit from iFixit cost $25 plus shipping. It included the battery and all the tools. It was a bit tricky to get the tiny screws back in but most I think most people should be able to do a DIY battery replacement on an older device that is out of warranty and has no waterproofing seals to worry about.
Be forewarned that nothing you do to an iPhone 4s or older device is going to make it fast ever again. Nothing. The last version of iOS that it runs pushes it to its limits. The world has moved on and if you’re also using any contemporary Apple device with newer apps the 4s will feel like a slow pig in deep mud unless you are an extremely patient person. As an iPod it’s okay.